Bump version (#2791)

* updated & added date related commands based on the new design

* added proper error handling when date format string is invalid

* fixed format issue

* fixed an issue caused due to the change in primitive Date type

* added `date list-timezone` command to list all supported time zones and updated `date to-timezone` accordingly

.azure/azure-pipelines.yml

@@ -1,11 +1,20 @@
 trigger:
-  - master
+  - main
 
 strategy:
   matrix:
     linux-stable:
       image: ubuntu-18.04
       style: 'unflagged'
+    linux-minimal:
+      image: ubuntu-18.04
+      style: 'minimal'
+    linux-extra:
+      image: ubuntu-18.04
+      style: 'extra'
+    linux-wasm:
+      image: ubuntu-18.04
+      style: 'wasm'
     macos-stable:
       image: macos-10.14
       style: 'unflagged'
@@ -34,28 +43,40 @@ steps:
       if [ -e /etc/debian_version ]
       then
         sudo apt-get -y install libxcb-composite0-dev libx11-dev
+        sudo npm install -g wasm-pack
       fi
       if [ "$(uname)" == "Darwin" ]; then
         curl https://sh.rustup.rs -sSf | sh -s -- -y --no-modify-path --default-toolchain "stable"
+        echo "Installing clippy"
+        rustup component add clippy --toolchain stable-x86_64-apple-darwin
         export PATH=$HOME/.cargo/bin:$PATH
       fi
-      rustup update
-      rustc -Vv
-      echo "##vso[task.prependpath]$HOME/.cargo/bin"
-      rustup component add rustfmt
+  #     rustup update
+  #     rustc -Vv
+  #     echo "##vso[task.prependpath]$HOME/.cargo/bin"
+  #     rustup component add rustfmt
     displayName: Install Rust
-  - bash: RUSTFLAGS="-D warnings" cargo test --all --features stable,test-bins
+  - bash: RUSTFLAGS="-D warnings" cargo test --all
     condition: eq(variables['style'], 'unflagged')
     displayName: Run tests
-  - bash: RUSTFLAGS="-D warnings" cargo clippy --all --features=stable -- -D clippy::result_unwrap_used -D clippy::option_unwrap_used
+  - bash: RUSTFLAGS="-D warnings" cargo clippy --all -- -D clippy::unwrap_used
     condition: eq(variables['style'], 'unflagged')
     displayName: Check clippy lints
-  - bash: NUSHELL_ENABLE_ALL_FLAGS=1 RUSTFLAGS="-D warnings" cargo test --all --features stable,test-bins
+  - bash: RUSTFLAGS="-D warnings" cargo test --all
     condition: eq(variables['style'], 'canary')
     displayName: Run tests
-  - bash: NUSHELL_ENABLE_ALL_FLAGS=1 RUSTFLAGS="-D warnings" cargo clippy --all --features=stable -- -D clippy::result_unwrap_used -D clippy::option_unwrap_used
+  - bash: cd samples/wasm && wasm-pack build
+    condition: eq(variables['style'], 'wasm')
+    displayName: Wasm build
+  - bash: RUSTFLAGS="-D warnings" cargo clippy --all -- -D clippy::unwrap_used
     condition: eq(variables['style'], 'canary')
     displayName: Check clippy lints
+  - bash: RUSTFLAGS="-D warnings" cargo test --all --no-default-features --features=rustyline-support
+    condition: eq(variables['style'], 'minimal')
+    displayName: Run tests
+  - bash: RUSTFLAGS="-D warnings" cargo test --all --features=extra
+    condition: eq(variables['style'], 'extra')
+    displayName: Run tests
   - bash: cargo fmt --all -- --check
     condition: eq(variables['style'], 'fmt')
     displayName: Lint

.cargo/config

@@ -1,3 +0,0 @@
-[build]
-
-#rustflags = ["--cfg", "data_processing_primitives"]

.cargo/config.toml

@@ -0,0 +1,6 @@
+# use LLD as linker on Windows because it could be faster
+# for full and incremental builds compared to default
+
+[target.x86_64-pc-windows-msvc]
+#linker = "lld-link.exe"
+rustflags = ["-C", "link-args=-stack:10000000"]

.circleci/config.yml

@@ -27,7 +27,7 @@ orbs:
 workflows:
   version: 2.0
 
-  # This builds on all pull requests to test, and ignores master
+  # This builds on all pull requests to test, and ignores main
   build_without_deploy:
     jobs:
       - docker/publish:
@@ -39,7 +39,7 @@ workflows:
           filters:
             branches:
               ignore:
-                - master
+                - main
           before_build:
             - pull_cache
           after_build:
@@ -73,7 +73,7 @@ workflows:
             branches:
               ignore: /.*/
             tags:
-              only: /^v.*/
+              only: /^\d+\.\d+\.\d+$/
           before_build:
             - run: docker pull quay.io/nushell/nu:latest
             - run: docker pull quay.io/nushell/nu-base:latest
@@ -98,11 +98,11 @@ workflows:
                    docker push quay.io/nushell/nu
 
 
-  # publish devel to Docker Hub on merge to master (doesn't build --release)
+  # publish devel to Docker Hub on merge to main (doesn't build --release)
   build_with_deploy_devel:
     jobs:
 
-      # Deploy devel tag on merge to master
+      # Deploy devel tag on merge to main
       - docker/publish:
           image: nushell/nu-base
           registry: quay.io
@@ -113,7 +113,7 @@ workflows:
             - pull_cache
           filters:
             branches:
-              only: master
+              only: main
           after_build:
             - run:
                 name: Build Multistage (smaller) container
@@ -137,7 +137,7 @@ workflows:
           filters:
             branches:
               only:
-                - master
+                - main
     jobs:
       - docker/publish:
           image: nushell/nu-base

.github/ISSUE_TEMPLATE/bug_report.md

@@ -23,8 +23,8 @@ A clear and concise description of what you expected to happen.
 If applicable, add screenshots to help explain your problem.
 
 **Configuration (please complete the following information):**
- - OS: [e.g. Windows]
- - Version [e.g. 0.4.0]
- - Optional features (if any)
+ - OS (e.g. Windows):
+ - Nu version (you can use the `version` command to find out): 
+ - Optional features (if any):
 
 Add any other context about the problem here.

.github/workflows/docker-publish.yml

@@ -13,7 +13,7 @@ jobs:
         - x86_64-unknown-linux-musl
         - x86_64-unknown-linux-gnu
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
     - name: Install rust-embedded/cross
       env: { VERSION: v0.1.16 }
       run: >-
@@ -62,7 +62,7 @@ jobs:
         - { tag: glibc,            base-image: scratch,                    arch: x86_64-unknown-linux-gnu,  plugin: false, use-patch: false}
         - { tag: musl,             base-image: scratch,                    arch: x86_64-unknown-linux-musl, plugin: false, use-patch: false}
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
     - uses: actions/download-artifact@master
       with: { name: '${{ matrix.arch }}', path: target/release }
     - name: Build and publish exact version

.github/workflows/release.yml

@@ -0,0 +1,286 @@
+name: Create Release Draft
+
+on:
+  push:
+    tags: ['[0-9]+.[0-9]+.[0-9]+*']
+
+jobs:
+  linux:
+    name: Build Linux
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v2
+
+      - name: Install libxcb
+        run: sudo apt-get install libxcb-composite0-dev
+
+      - name: Set up cargo
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+
+      - name: Build
+        uses: actions-rs/cargo@v1
+        with:
+          command: build
+          args: --release --all --features=extra
+
+      - name: Create output directory
+        run: mkdir output
+
+      - name: Copy files to output
+        run: |
+          cp target/release/nu target/release/nu_plugin_* output/
+          cp README.build.txt output/README.txt
+          cp LICENSE output/LICENSE
+          rm output/*.d
+          rm output/nu_plugin_core_*
+          rm output/nu_plugin_extra_*
+
+      # Note: If OpenSSL changes, this path will need to be updated
+      - name: Copy OpenSSL to output
+        run: cp /usr/lib/x86_64-linux-gnu/libssl.so.1.1 output/
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v2
+        with:
+          name: linux
+          path: output/*
+
+  macos:
+    name: Build macOS
+    runs-on: macos-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v2
+
+      - name: Set up cargo
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+
+      - name: Build
+        uses: actions-rs/cargo@v1
+        with:
+          command: build
+          args: --release --all --features=extra
+
+      - name: Create output directory
+        run: mkdir output
+
+      - name: Copy files to output
+        run: |
+          cp target/release/nu target/release/nu_plugin_* output/
+          cp README.build.txt output/README.txt
+          cp LICENSE output/LICENSE
+          rm output/*.d
+          rm output/nu_plugin_core_*
+          rm output/nu_plugin_extra_*
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v2
+        with:
+          name: macos
+          path: output/*
+
+  windows:
+    name: Build Windows
+    runs-on: windows-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v2
+
+      - name: Set up cargo
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+
+      - name: Add cargo-wix subcommand
+        uses: actions-rs/cargo@v1
+        with:
+          command: install
+          args: cargo-wix
+
+      - name: Build
+        uses: actions-rs/cargo@v1
+        with:
+          command: build
+          args: --release --all --features=extra
+
+      - name: Create output directory
+        run: mkdir output
+
+      - name: Download Less Binary
+        run: Invoke-WebRequest -Uri "https://github.com/jftuga/less-Windows/releases/download/less-v562.0/less.exe" -OutFile "target\release\less.exe"
+
+      - name: Download Less License
+        run: Invoke-WebRequest -Uri "https://raw.githubusercontent.com/jftuga/less-Windows/master/LICENSE" -OutFile "target\release\LICENSE-for-less.txt"
+
+      - name: Copy files to output
+        run: |
+          cp target\release\nu.exe output\
+          cp LICENSE output\
+          cp target\release\LICENSE-for-less.txt output\
+          rm target\release\nu_plugin_core_*.exe
+          rm target\release\nu_plugin_extra_*.exe
+          cp target\release\nu_plugin_*.exe output\
+          cp README.build.txt output\README.txt
+          cp target\release\less.exe output\
+      # Note: If the version of `less.exe` needs to be changed, update this URL
+      # Similarly, if `less.exe` is checked into the repo, copy from the local path here
+      # moved this stuff down to create wix after we download less
+
+      - name: Create msi with wix
+        uses: actions-rs/cargo@v1
+        with:
+          command: wix
+          args: --no-build --nocapture --output target\wix\nushell-windows.msi
+
+      - name: Upload installer
+        uses: actions/upload-artifact@v2
+        with:
+          name: windows-installer
+          path: target\wix\nushell-windows.msi
+
+      - name: Upload zip
+        uses: actions/upload-artifact@v2
+        with:
+          name: windows-zip
+          path: output\*
+
+  release:
+    name: Publish Release
+    runs-on: ubuntu-latest
+    needs:
+      - linux
+      - macos
+      - windows
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v2
+
+      - name: Determine Release Info
+        id: info
+        env:
+          GITHUB_REF: ${{ github.ref }}
+        run: |
+          VERSION=${GITHUB_REF##*/}
+          MAJOR=${VERSION%%.*}
+          MINOR=${VERSION%.*}
+          MINOR=${MINOR#*.}
+          PATCH=${VERSION##*.}
+          echo "::set-output name=version::${VERSION}"
+          echo "::set-output name=linuxdir::nu_${MAJOR}_${MINOR}_${PATCH}_linux"
+          echo "::set-output name=macosdir::nu_${MAJOR}_${MINOR}_${PATCH}_macOS"
+          echo "::set-output name=windowsdir::nu_${MAJOR}_${MINOR}_${PATCH}_windows"
+          echo "::set-output name=innerdir::nushell-${VERSION}"
+
+      - name: Create Release Draft
+        id: create_release
+        uses: actions/create-release@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          tag_name: ${{ github.ref }}
+          release_name: ${{ steps.info.outputs.version }} Release
+          draft: true
+
+      - name: Create Linux Directory
+        run: mkdir -p ${{ steps.info.outputs.linuxdir }}/${{ steps.info.outputs.innerdir }}
+
+      - name: Download Linux Artifacts
+        uses: actions/download-artifact@v2
+        with:
+          name: linux
+          path: ${{ steps.info.outputs.linuxdir }}/${{ steps.info.outputs.innerdir }}
+
+      - name: Restore Linux File Modes
+        run: |
+          chmod 755 ${{ steps.info.outputs.linuxdir }}/${{ steps.info.outputs.innerdir }}/nu*
+          chmod 755 ${{ steps.info.outputs.linuxdir }}/${{ steps.info.outputs.innerdir }}/libssl*
+
+      - name: Create Linux tarball
+        run: tar -zcvf ${{ steps.info.outputs.linuxdir }}.tar.gz ${{ steps.info.outputs.linuxdir }}
+
+      - name: Upload Linux Artifact
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.create_release.outputs.upload_url }}
+          asset_path: ./${{ steps.info.outputs.linuxdir }}.tar.gz
+          asset_name: ${{ steps.info.outputs.linuxdir }}.tar.gz
+          asset_content_type: application/gzip
+
+      - name: Create macOS Directory
+        run: mkdir -p ${{ steps.info.outputs.macosdir }}/${{ steps.info.outputs.innerdir }}
+
+      - name: Download macOS Artifacts
+        uses: actions/download-artifact@v2
+        with:
+          name: macos
+          path: ${{ steps.info.outputs.macosdir }}/${{ steps.info.outputs.innerdir }}
+
+      - name: Restore macOS File Modes
+        run: chmod 755 ${{ steps.info.outputs.macosdir }}/${{ steps.info.outputs.innerdir }}/nu*
+
+      - name: Create macOS Archive
+        run: zip -r ${{ steps.info.outputs.macosdir }}.zip ${{ steps.info.outputs.macosdir }}
+
+      - name: Upload macOS Artifact
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.create_release.outputs.upload_url }}
+          asset_path: ./${{ steps.info.outputs.macosdir }}.zip
+          asset_name: ${{ steps.info.outputs.macosdir }}.zip
+          asset_content_type: application/zip
+
+      - name: Create Windows Directory
+        run: mkdir -p ${{ steps.info.outputs.windowsdir }}/${{ steps.info.outputs.innerdir }}
+
+      - name: Download Windows zip
+        uses: actions/download-artifact@v2
+        with:
+          name: windows-zip
+          path: ${{ steps.info.outputs.windowsdir }}/${{ steps.info.outputs.innerdir }}
+
+      - name: Show Windows Artifacts
+        run: ls -la ${{ steps.info.outputs.windowsdir }}/${{ steps.info.outputs.innerdir }}
+
+      - name: Create macOS Archive
+        run: zip -r ${{ steps.info.outputs.windowsdir }}.zip ${{ steps.info.outputs.windowsdir }}
+
+      - name: Upload Windows zip
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.create_release.outputs.upload_url }}
+          asset_path: ./${{ steps.info.outputs.windowsdir }}.zip
+          asset_name: ${{ steps.info.outputs.windowsdir }}.zip
+          asset_content_type: application/zip
+
+      - name: Download Windows installer
+        uses: actions/download-artifact@v2
+        with:
+          name: windows-installer
+          path: ./
+          
+      - name: Upload Windows installer
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.create_release.outputs.upload_url }}
+          asset_path: ./nushell-windows.msi
+          asset_name: ${{ steps.info.outputs.windowsdir }}.msi
+          asset_content_type: applictaion/x-msi

.gitignore

@@ -11,3 +11,12 @@ debian/debhelper-build-stamp
 debian/files
 debian/nu.substvars
 debian/nu/
+
+# macOS junk
+.DS_Store
+
+# JetBrains' IDE items
+.idea/*
+
+# VSCode's IDE items
+.vscode/*

.gitpod.Dockerfile

@@ -1,9 +1,18 @@
 FROM gitpod/workspace-full
 
+# Gitpod will not rebuild Nushell's dev image unless *some* change is made to this Dockerfile.
+# To force a rebuild, simply increase this counter:
+ENV TRIGGER_REBUILD 1
+
 USER gitpod
 
 RUN sudo apt-get update && \
     sudo apt-get install -y \
         libssl-dev \
         libxcb-composite0-dev \
-        pkg-config
+        pkg-config \
+        libpython3.6 \
+        rust-lldb \
+    && sudo rm -rf /var/lib/apt/lists/*
+
+ENV RUST_LLDB=/usr/bin/lldb-11

.gitpod.yml

@@ -1,23 +1,19 @@
 image:
   file: .gitpod.Dockerfile
 tasks:
-  - init: cargo install --path . --force --features=stable
+  - name: Clippy
+    init: cargo clippy --all --features=stable -- -D clippy::result_unwrap_used -D clippy::option_unwrap_used
+  - name: Testing
+    init: cargo test --all --features=stable,test-bins
+  - name: Build
+    init: cargo build --features=stable
+  - name: Nu
+    init: cargo install --path . --features=stable
     command: nu
 github:
   prebuilds:
-    # enable for the master/default branch (defaults to true)
-    master: true
-    # enable for all branches in this repo (defaults to false)
     branches: true
-    # enable for pull requests coming from this repo (defaults to true)
-    pullRequests: true
-    # enable for pull requests coming from forks (defaults to false)
     pullRequestsFromForks: true
-    # add a "Review in Gitpod" button as a comment to pull requests (defaults to true)
-    addComment: true
-    # add a "Review in Gitpod" button to pull requests (defaults to false)
-    addBadge: false
-    # add a label once the prebuild is ready to pull requests (defaults to false)
     addLabel: prebuilt-in-gitpod
 vscode:
   extensions:
@@ -25,5 +21,5 @@ vscode:
     - Swellaby.vscode-rust-test-adapter@0.11.0:Xg+YeZZQiVpVUsIkH+uiiw==
     - serayuzgur.crates@0.4.7:HMkoguLcXp9M3ud7ac3eIw==
     - belfz.search-crates-io@1.2.1:kSLnyrOhXtYPjQpKnMr4eQ==
-    - vadimcn.vscode-lldb@1.4.5:lwHCNwtm0kmOBXeQUIPGMQ==
     - bungcip.better-toml@0.3.2:3QfgGxxYtGHfJKQU7H0nEw==
+    - webfreak.debug@0.24.0:1zVcRsAhewYEX3/A9xjMNw==

.theia/launch.json

@@ -0,0 +1,14 @@
+{
+  "version": "0.2.0",
+  "configurations": [
+      {
+          "type": "gdb",
+          "request": "launch",
+          "name": "Debug Rust Code",
+          "preLaunchTask": "cargo",
+          "target": "${workspaceFolder}/target/debug/nu",
+          "cwd": "${workspaceFolder}",
+          "valuesFormatting": "parseText"
+      }
+  ]
+}

.theia/tasks.json

@@ -0,0 +1,12 @@
+{
+    "tasks": [
+        {
+            "command": "cargo",
+            "args": [
+                "build"
+            ],
+            "type": "process",
+            "label": "cargo",
+        }
+    ],
+}

CODE_OF_CONDUCT.md

@@ -55,7 +55,7 @@ a project may be further defined and clarified by project maintainers.
 ## Enforcement
 
 Instances of abusive, harassing, or otherwise unacceptable behavior may be
-reported by contacting the project team at wycats@gmail.com. All
+reported by contacting the project team at wycats@gmail.com via email or by reaching out to @jturner, @gedge, or @andras_io on discord. All
 complaints will be reviewed and investigated and will result in a response that
 is deemed necessary and appropriate to the circumstances. The project team is
 obligated to maintain confidentiality with regard to the reporter of an incident.
@@ -68,9 +68,9 @@ members of the project's leadership.
 ## Attribution
 
 This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
-available at https://www.contributor-covenant.org/version/1/4/code-of-conduct.html
+available at <https://www.contributor-covenant.org/version/1/4/code-of-conduct.html>
 
 [homepage]: https://www.contributor-covenant.org
 
 For answers to common questions about this code of conduct, see
-https://www.contributor-covenant.org/faq
+<https://www.contributor-covenant.org/faq>

CONTRIBUTING.md

@@ -1,3 +1,5 @@
+# Contributing
+
 Welcome to nushell!
 
 *Note: for a more complete guide see [The nu contributor book](https://github.com/nushell/contributor-book)*
@@ -9,3 +11,65 @@ For speedy contributions open it in Gitpod, nu will be pre-installed with the la
 To get live support from the community see our [Discord](https://discordapp.com/invite/NtAbbGn), [Twitter](https://twitter.com/nu_shell) or file an issue or feature request here on [GitHub](https://github.com/nushell/nushell/issues/new/choose)!
 <!--WIP-->
 
+## Developing
+
+### Set up
+
+This is no different than other Rust projects.
+
+```bash
+git clone https://github.com/nushell/nushell
+cd nushell
+cargo build
+```
+
+### Useful Commands
+
+- Build and run Nushell:
+
+  ```shell
+  cargo build --release && cargo run --release
+  ```
+
+- Build and run with extra features:
+  ```shell
+  cargo build --release --features=extra && cargo run --release --features=extra
+  ```
+
+- Run Clippy on Nushell:
+
+  ```shell
+  cargo clippy --all --features=stable
+  ```
+
+- Run all tests:
+
+  ```shell
+  cargo test --all --features=stable
+  ```
+
+- Run all tests for a specific command
+
+  ```shell
+  cargo test --package nu-cli --test main -- commands::<command_name_here>
+  ```
+
+- Check to see if there are code formatting issues
+
+  ```shell
+  cargo fmt --all -- --check
+  ```
+
+- Format the code in the project
+
+  ```shell
+  cargo fmt --all
+  ```
+
+### Debugging Tips
+
+- To view verbose logs when developing, enable the `trace` log level.
+
+  ```shell
+  cargo build --release --features=extra && cargo run --release --features=extra -- --loglevel trace
+  ```

Cargo.toml

@@ -1,16 +1,16 @@
 [package]
-name = "nu"
-version = "0.13.0"
 authors = ["The Nu Project Contributors"]
-description = "A new type of shell"
-license = "MIT"
-edition = "2018"
-readme = "README.md"
 default-run = "nu"
-repository = "https://github.com/nushell/nushell"
-homepage = "https://www.nushell.sh"
+description = "A new type of shell"
 documentation = "https://www.nushell.sh/book/"
+edition = "2018"
 exclude = ["images"]
+homepage = "https://www.nushell.sh"
+license = "MIT"
+name = "nu"
+readme = "README.md"
+repository = "https://github.com/nushell/nushell"
+version = "0.24.0"
 
 [workspace]
 members = ["crates/*/"]
@@ -18,96 +18,113 @@ members = ["crates/*/"]
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-nu-cli = { version = "0.13.0", path = "./crates/nu-cli" }
-nu-source = { version = "0.13.0", path = "./crates/nu-source" }
-nu-plugin = { version = "0.13.0", path = "./crates/nu-plugin" }
-nu-protocol = { version = "0.13.0", path = "./crates/nu-protocol" }
-nu-errors = { version = "0.13.0", path = "./crates/nu-errors" }
-nu-parser = { version = "0.13.0", path = "./crates/nu-parser" }
-nu-value-ext = { version = "0.13.0", path = "./crates/nu-value-ext" }
-nu_plugin_average = { version = "0.13.0", path = "./crates/nu_plugin_average", optional=true }
-nu_plugin_binaryview = { version = "0.13.0", path = "./crates/nu_plugin_binaryview", optional=true }
-nu_plugin_fetch = { version = "0.13.0", path = "./crates/nu_plugin_fetch", optional=true }
-nu_plugin_inc = { version = "0.13.0", path = "./crates/nu_plugin_inc", optional=true }
-nu_plugin_match = { version = "0.13.0", path = "./crates/nu_plugin_match", optional=true }
-nu_plugin_post = { version = "0.13.0", path = "./crates/nu_plugin_post", optional=true }
-nu_plugin_ps = { version = "0.13.0", path = "./crates/nu_plugin_ps", optional=true }
-nu_plugin_str = { version = "0.13.0", path = "./crates/nu_plugin_str", optional=true }
-nu_plugin_sys = { version = "0.13.0", path = "./crates/nu_plugin_sys", optional=true }
-nu_plugin_textview = { version = "0.13.0", path = "./crates/nu_plugin_textview", optional=true }
-nu_plugin_tree = { version = "0.13.0", path = "./crates/nu_plugin_tree", optional=true }
+nu-cli = {version = "0.24.0", path = "./crates/nu-cli"}
+nu-data = {version = "0.24.0", path = "./crates/nu-data"}
+nu-errors = {version = "0.24.0", path = "./crates/nu-errors"}
+nu-parser = {version = "0.24.0", path = "./crates/nu-parser"}
+nu-plugin = {version = "0.24.0", path = "./crates/nu-plugin"}
+nu-protocol = {version = "0.24.0", path = "./crates/nu-protocol"}
+nu-source = {version = "0.24.0", path = "./crates/nu-source"}
+nu-value-ext = {version = "0.24.0", path = "./crates/nu-value-ext"}
 
-crossterm = { version = "0.17.2", optional = true }
-semver = { version = "0.9.0", optional = true }
-syntect = { version = "4.1", default-features = false, features = ["default-fancy"], optional = true}
-url = { version = "2.1.1", optional = true }
+nu_plugin_binaryview = {version = "0.24.0", path = "./crates/nu_plugin_binaryview", optional = true}
+nu_plugin_chart = {version = "0.24.0", path = "./crates/nu_plugin_chart", optional = true}
+nu_plugin_fetch = {version = "0.24.0", path = "./crates/nu_plugin_fetch", optional = true}
+nu_plugin_from_bson = {version = "0.24.0", path = "./crates/nu_plugin_from_bson", optional = true}
+nu_plugin_from_sqlite = {version = "0.24.0", path = "./crates/nu_plugin_from_sqlite", optional = true}
+nu_plugin_inc = {version = "0.24.0", path = "./crates/nu_plugin_inc", optional = true}
+nu_plugin_match = {version = "0.24.0", path = "./crates/nu_plugin_match", optional = true}
+nu_plugin_post = {version = "0.24.0", path = "./crates/nu_plugin_post", optional = true}
+nu_plugin_ps = {version = "0.24.0", path = "./crates/nu_plugin_ps", optional = true}
+nu_plugin_s3 = {version = "0.24.0", path = "./crates/nu_plugin_s3", optional = true}
+nu_plugin_start = {version = "0.24.0", path = "./crates/nu_plugin_start", optional = true}
+nu_plugin_sys = {version = "0.24.0", path = "./crates/nu_plugin_sys", optional = true}
+nu_plugin_textview = {version = "0.24.0", path = "./crates/nu_plugin_textview", optional = true}
+nu_plugin_to_bson = {version = "0.24.0", path = "./crates/nu_plugin_to_bson", optional = true}
+nu_plugin_to_sqlite = {version = "0.24.0", path = "./crates/nu_plugin_to_sqlite", optional = true}
+nu_plugin_tree = {version = "0.24.0", path = "./crates/nu_plugin_tree", optional = true}
+nu_plugin_xpath = {version = "0.24.0", path = "./crates/nu_plugin_xpath", optional = true}
+nu_plugin_selector = {version = "0.24.0", path = "./crates/nu_plugin_selector", optional = true}
 
-clap = "2.33.0"
-ctrlc = "3.1.4"
-dunce = "1.0.0"
-futures = { version = "0.3", features = ["compat", "io-compat"] }
-log = "0.4.8"
+# Required to bootstrap the main binary
+clap = "2.33.3"
+ctrlc = {version = "3.1.6", optional = true}
+futures = {version = "0.3.5", features = ["compat", "io-compat"]}
+log = "0.4.11"
 pretty_env_logger = "0.4.0"
+itertools = "0.9.0"
 
 [dev-dependencies]
-nu-test-support = { version = "0.13.0", path = "./crates/nu-test-support" }
+dunce = "1.0.1"
+nu-test-support = {version = "0.24.0", path = "./crates/nu-test-support"}
 
 [build-dependencies]
-toml = "0.5.6"
-serde = { version = "1.0.106", features = ["derive"] }
-nu-build = { version = "0.13.0", path = "./crates/nu-build" }
 
 [features]
-# Test executables
-test-bins = []
+ctrlc-support = ["nu-cli/ctrlc"]
+directories-support = ["nu-cli/directories", "nu-cli/dirs", "nu-data/directories", "nu-data/dirs"]
+git-support = ["nu-cli/git2"]
+ptree-support = ["nu-cli/ptree"]
+rich-benchmark = ["nu-cli/rich-benchmark"]
+rustyline-support = ["nu-cli/rustyline-support"]
+term-support = ["nu-cli/term"]
+uuid-support = ["nu-cli/uuid_crate"]
+which-support = ["nu-cli/ichwh", "nu-cli/which"]
 
-default = ["sys", "ps", "textview", "inc", "str"]
-stable = ["default", "starship-prompt", "binaryview", "match", "tree", "average", "post", "fetch", "clipboard-cli", "trash-support"]
+default = [
+  "sys",
+  "ps",
+  "textview",
+  "inc",
+  "git-support",
+  "directories-support",
+  "ctrlc-support",
+  "which-support",
+  "ptree-support",
+  "term-support",
+  "uuid-support",
+  "rustyline-support",
+  "match",
+  "post",
+  "fetch",
+  "rich-benchmark",
+  "zip-support"
+]
+extra = ["default", "binaryview", "tree", "clipboard-cli", "trash-support", "start", "bson", "sqlite", "s3", "chart", "xpath", "selector"]
+stable = ["default"]
 
-# Default
-textview = ["crossterm", "syntect", "url", "nu_plugin_textview"]
-sys = ["nu_plugin_sys"]
-ps = ["nu_plugin_ps"]
-inc = ["semver", "nu_plugin_inc"]
-str = ["nu_plugin_str"]
+wasi = ["inc", "match", "directories-support", "ptree-support", "match", "tree", "rustyline-support"]
 
-# Stable
-average = ["nu_plugin_average"]
-binaryview = ["nu_plugin_binaryview"]
+trace = ["nu-parser/trace"]
+
+# Stable (Default)
 fetch = ["nu_plugin_fetch"]
+inc = ["nu_plugin_inc"]
 match = ["nu_plugin_match"]
 post = ["nu_plugin_post"]
-trace = ["nu-parser/trace"]
-tree = ["nu_plugin_tree"]
+ps = ["nu_plugin_ps"]
+sys = ["nu_plugin_sys"]
+textview = ["nu_plugin_textview"]
+zip-support = ["nu-cli/zip"]
 
+# Extra
+binaryview = ["nu_plugin_binaryview"]
+bson = ["nu_plugin_from_bson", "nu_plugin_to_bson"]
+chart = ["nu_plugin_chart"]
 clipboard-cli = ["nu-cli/clipboard-cli"]
-starship-prompt = ["nu-cli/starship-prompt"]
+s3 = ["nu_plugin_s3"]
+sqlite = ["nu_plugin_from_sqlite", "nu_plugin_to_sqlite"]
+start = ["nu_plugin_start"]
 trash-support = ["nu-cli/trash-support"]
+tree = ["nu_plugin_tree"]
+xpath = ["nu_plugin_xpath"]
+selector = ["nu_plugin_selector"]
 
-[[bin]]
-name = "fail"
-path = "crates/nu-test-support/src/bins/fail.rs"
-required-features = ["test-bins"]
-
-[[bin]]
-name = "chop"
-path = "crates/nu-test-support/src/bins/chop.rs"
-required-features = ["test-bins"]
-
-[[bin]]
-name = "cococo"
-path = "crates/nu-test-support/src/bins/cococo.rs"
-required-features = ["test-bins"]
-
-[[bin]]
-name = "nonu"
-path = "crates/nu-test-support/src/bins/nonu.rs"
-required-features = ["test-bins"]
-
-[[bin]]
-name = "iecho"
-path = "crates/nu-test-support/src/bins/iecho.rs"
-required-features = ["test-bins"]
+[profile.release]
+#strip = "symbols" #Couldn't get working +nightly
+opt-level = 'z' #Optimize for size
+lto = true #Link Time Optimization
+codegen-units = 1 #Reduce parallel codegen units
 
 # Core plugins that ship with `cargo install nu` by default
 # Currently, Cargo limits us to installing only one binary
@@ -127,47 +144,88 @@ name = "nu_plugin_core_ps"
 path = "src/plugins/nu_plugin_core_ps.rs"
 required-features = ["ps"]
 
-[[bin]]
-name = "nu_plugin_core_str"
-path = "src/plugins/nu_plugin_core_str.rs"
-required-features = ["str"]
-
 [[bin]]
 name = "nu_plugin_core_sys"
 path = "src/plugins/nu_plugin_core_sys.rs"
 required-features = ["sys"]
 
-# Stable plugins
 [[bin]]
-name = "nu_plugin_stable_average"
-path = "src/plugins/nu_plugin_stable_average.rs"
-required-features = ["average"]
-
-[[bin]]
-name = "nu_plugin_stable_fetch"
-path = "src/plugins/nu_plugin_stable_fetch.rs"
+name = "nu_plugin_core_fetch"
+path = "src/plugins/nu_plugin_core_fetch.rs"
 required-features = ["fetch"]
 
 [[bin]]
-name = "nu_plugin_stable_binaryview"
-path = "src/plugins/nu_plugin_stable_binaryview.rs"
-required-features = ["binaryview"]
-
-[[bin]]
-name = "nu_plugin_stable_match"
-path = "src/plugins/nu_plugin_stable_match.rs"
+name = "nu_plugin_core_match"
+path = "src/plugins/nu_plugin_core_match.rs"
 required-features = ["match"]
 
 [[bin]]
-name = "nu_plugin_stable_post"
-path = "src/plugins/nu_plugin_stable_post.rs"
+name = "nu_plugin_core_post"
+path = "src/plugins/nu_plugin_core_post.rs"
 required-features = ["post"]
 
+# Extra plugins
+
 [[bin]]
-name = "nu_plugin_stable_tree"
-path = "src/plugins/nu_plugin_stable_tree.rs"
+name = "nu_plugin_extra_binaryview"
+path = "src/plugins/nu_plugin_extra_binaryview.rs"
+required-features = ["binaryview"]
+
+[[bin]]
+name = "nu_plugin_extra_tree"
+path = "src/plugins/nu_plugin_extra_tree.rs"
 required-features = ["tree"]
 
+[[bin]]
+name = "nu_plugin_extra_start"
+path = "src/plugins/nu_plugin_extra_start.rs"
+required-features = ["start"]
+
+[[bin]]
+name = "nu_plugin_extra_s3"
+path = "src/plugins/nu_plugin_extra_s3.rs"
+required-features = ["s3"]
+
+[[bin]]
+name = "nu_plugin_extra_chart_bar"
+path = "src/plugins/nu_plugin_extra_chart_bar.rs"
+required-features = ["chart"]
+
+[[bin]]
+name = "nu_plugin_extra_chart_line"
+path = "src/plugins/nu_plugin_extra_chart_line.rs"
+required-features = ["chart"]
+
+[[bin]]
+name = "nu_plugin_extra_xpath"
+path = "src/plugins/nu_plugin_extra_xpath.rs"
+required-features = ["xpath"]
+
+[[bin]]
+name = "nu_plugin_extra_selector"
+path = "src/plugins/nu_plugin_extra_selector.rs"
+required-features = ["selector"]
+
+[[bin]]
+name = "nu_plugin_extra_from_bson"
+path = "src/plugins/nu_plugin_extra_from_bson.rs"
+required-features = ["bson"]
+
+[[bin]]
+name = "nu_plugin_extra_to_bson"
+path = "src/plugins/nu_plugin_extra_to_bson.rs"
+required-features = ["bson"]
+
+[[bin]]
+name = "nu_plugin_extra_from_sqlite"
+path = "src/plugins/nu_plugin_extra_from_sqlite.rs"
+required-features = ["sqlite"]
+
+[[bin]]
+name = "nu_plugin_extra_to_sqlite"
+path = "src/plugins/nu_plugin_extra_to_sqlite.rs"
+required-features = ["sqlite"]
+
 # Main nu binary
 [[bin]]
 name = "nu"

README.build.txt

@@ -0,0 +1 @@
+Nu will look for the plugins in your PATH on startup. While nu will have some functionality without them, for full functionality you'll need to copy them into your path so they can be loaded.

README.md

@@ -1,17 +1,19 @@
+# README
+
 [![Gitpod Ready-to-Code](https://img.shields.io/badge/Gitpod-Ready--to--Code-blue?logo=gitpod)](https://gitpod.io/#https://github.com/nushell/nushell)
 [![Crates.io](https://img.shields.io/crates/v/nu.svg)](https://crates.io/crates/nu)
 [![Build Status](https://dev.azure.com/nushell/nushell/_apis/build/status/nushell.nushell?branchName=master)](https://dev.azure.com/nushell/nushell/_build/latest?definitionId=2&branchName=master)
 [![Discord](https://img.shields.io/discord/601130461678272522.svg?logo=discord)](https://discord.gg/NtAbbGn)
 [![The Changelog #363](https://img.shields.io/badge/The%20Changelog-%23363-61c192.svg)](https://changelog.com/podcast/363)
+[![@nu_shell](https://img.shields.io/badge/twitter-@nu_shell-1DA1F3?style=flat-square)](https://twitter.com/nu_shell)
 
-
-# Nu Shell
+## Nushell
 
 A new type of shell.
 
 ![Example of nushell](images/nushell-autocomplete.gif "Example of nushell")
 
-# Status
+## Status
 
 This project has reached a minimum-viable product level of quality.
 While contributors dogfood it as their daily driver, it may be unstable for some commands.
@@ -21,7 +23,7 @@ Its design is also subject to change as it matures.
 Nu comes with a set of built-in commands (listed below).
 If a command is unknown, the command will shell-out and execute it (using cmd on Windows or bash on Linux and macOS), correctly passing through stdin, stdout, and stderr, so things like your daily git workflows and even `vim` will work just fine.
 
-# Learning more
+## Learning more
 
 There are a few good resources to learn about Nu.
 There is a [book](https://www.nushell.sh/book/) about Nu that is currently in progress.
@@ -32,45 +34,45 @@ There are also [good first issues](https://github.com/nushell/nushell/issues?q=i
 
 We also have an active [Discord](https://discord.gg/NtAbbGn) and [Twitter](https://twitter.com/nu_shell) if you'd like to come and chat with us.
 
-You can also find more learning resources in our [documentation](https://www.nushell.sh/documentation.html) site.
+You can also find information on more specific topics in our [cookbook](https://www.nushell.sh/cookbook/).
 
 Try it in Gitpod.
 
 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/#https://github.com/nushell/nushell)
 
-# Installation
+## Installation
 
-## Local
+### Local
 
-Up-to-date installation instructions can be found in the [installation chapter of the book](https://www.nushell.sh/book/en/installation.html).  **Windows users**: please note that Nu works on Windows 10 and does not currently have Windows 7/8.1 support.
+Up-to-date installation instructions can be found in the [installation chapter of the book](https://www.nushell.sh/book/installation.html).  **Windows users**: please note that Nu works on Windows 10 and does not currently have Windows 7/8.1 support.
 
-To build Nu, you will need to use the **latest stable (1.39 or later)** version of the compiler.
+To build Nu, you will need to use the **latest stable (1.47 or later)** version of the compiler.
 
 Required dependencies:
 
 * pkg-config and libssl (only needed on Linux)
-  * on Debian/Ubuntu: `apt install pkg-config libssl-dev`
+  * On Debian/Ubuntu: `apt install pkg-config libssl-dev`
 
 Optional dependencies:
 
 * To use Nu with all possible optional features enabled, you'll also need the following:
-  * on Linux (on Debian/Ubuntu): `apt install libxcb-composite0-dev libx11-dev`
+  * On Linux (on Debian/Ubuntu): `apt install libxcb-composite0-dev libx11-dev`
 
 To install Nu via cargo (make sure you have installed [rustup](https://rustup.rs/) and the latest stable compiler via `rustup install stable`):
 
-```
+```bash
 cargo install nu
 ```
 
 You can also build Nu yourself with all the bells and whistles (be sure to have installed the [dependencies](https://www.nushell.sh/book/en/installation.html#dependencies) for your platform), once you have checked out this repo with git:
 
-```
-cargo build --workspace --features=stable
+```bash
+cargo build --workspace --features=extra
 ```
 
-## Docker
+### Docker
 
-### Quickstart
+#### Quickstart
 
 Want to try Nu right away? Execute the following to get started.
 
@@ -78,14 +80,14 @@ Want to try Nu right away? Execute the following to get started.
 docker run -it quay.io/nushell/nu:latest
 ```
 
-### Guide
+#### Guide
 
 If you want to pull a pre-built container, you can browse tags for the [nushell organization](https://quay.io/organization/nushell)
 on Quay.io. Pulling a container would come down to:
 
 ```bash
-$ docker pull quay.io/nushell/nu
-$ docker pull quay.io/nushell/nu-base
+docker pull quay.io/nushell/nu
+docker pull quay.io/nushell/nu-base
 ```
 
 Both "nu-base" and "nu" provide the nu binary, however nu-base also includes the source code at `/code`
@@ -95,41 +97,41 @@ Optionally, you can also build the containers locally using the [dockerfiles pro
 To build the base image:
 
 ```bash
-$ docker build -f docker/Dockerfile.nu-base -t nushell/nu-base .
+docker build -f docker/Dockerfile.nu-base -t nushell/nu-base .
 ```
 
 And then to build the smaller container (using a Multistage build):
 
 ```bash
-$ docker build -f docker/Dockerfile -t nushell/nu .
+docker build -f docker/Dockerfile -t nushell/nu .
 ```
 
 Either way, you can run either container as follows:
 
 ```bash
-$ docker run -it nushell/nu-base
-$ docker run -it nushell/nu
+docker run -it nushell/nu-base
+docker run -it nushell/nu
 /> exit
 ```
 
 The second container is a bit smaller if the size is important to you.
 
-## Packaging status
+### Packaging status
 
 [![Packaging status](https://repology.org/badge/vertical-allrepos/nushell.svg)](https://repology.org/project/nushell/versions)
 
-### Fedora
+#### Fedora
 
 [COPR repo](https://copr.fedorainfracloud.org/coprs/atim/nushell/): `sudo dnf copr enable atim/nushell -y && sudo dnf install nushell -y`
 
-# Philosophy
+## Philosophy
 
 Nu draws inspiration from projects like PowerShell, functional programming languages, and modern CLI tools.
 Rather than thinking of files and services as raw streams of text, Nu looks at each input as something with structure.
 For example, when you list the contents of a directory, what you get back is a table of rows, where each row represents an item in that directory.
 These values can be piped through a series of steps, in a series of commands called a 'pipeline'.
 
-## Pipelines
+### Pipelines
 
 In Unix, it's common to pipe between commands to split up a sophisticated command over multiple steps.
 Nu takes this a step further and builds heavily on the idea of _pipelines_.
@@ -138,104 +140,110 @@ Additionally, commands can output structured data (you can think of this as a th
 Commands that work in the pipeline fit into one of three categories:
 
 * Commands that produce a stream (eg, `ls`)
-* Commands that filter a stream (eg, `where type == "Directory"`)
+* Commands that filter a stream (eg, `where type == "Dir"`)
 * Commands that consume the output of the pipeline (eg, `autoview`)
 
 Commands are separated by the pipe symbol (`|`) to denote a pipeline flowing left to right.
 
-```
-/home/jonathan/Source/nushell(master)> ls | where type == "Directory" | autoview
-────┬───────────┬───────────┬──────────┬────────┬──────────────┬────────────────
- #  │ name      │ type      │ readonly │ size   │ accessed     │ modified
-────┼───────────┼───────────┼──────────┼────────┼──────────────┼────────────────
-  0 │ .azure    │ Directory │          │ 4.1 KB │ 2 months ago │ a day ago
-  1 │ target    │ Directory │          │ 4.1 KB │ 3 days ago   │ 3 days ago
-  2 │ images    │ Directory │          │ 4.1 KB │ 2 months ago │ 2 weeks ago
-  3 │ tests     │ Directory │          │ 4.1 KB │ 2 months ago │ 37 minutes ago
-  4 │ tmp       │ Directory │          │ 4.1 KB │ 2 weeks ago  │ 2 weeks ago
-  5 │ src       │ Directory │          │ 4.1 KB │ 2 months ago │ 37 minutes ago
-  6 │ assets    │ Directory │          │ 4.1 KB │ a month ago  │ a month ago
-  7 │ docs      │ Directory │          │ 4.1 KB │ 2 months ago │ 2 months ago
-────┴───────────┴───────────┴──────────┴────────┴──────────────┴────────────────
+```shell
+> ls | where type == "Dir" | autoview
+───┬────────┬──────┬───────┬──────────────
+ # │ name   │ type │ size  │ modified
+───┼────────┼──────┼───────┼──────────────
+ 0 │ assets │ Dir  │ 128 B │ 5 months ago
+ 1 │ crates │ Dir  │ 704 B │ 50 mins ago
+ 2 │ debian │ Dir  │ 352 B │ 5 months ago
+ 3 │ docker │ Dir  │ 288 B │ 3 months ago
+ 4 │ docs   │ Dir  │ 192 B │ 50 mins ago
+ 5 │ images │ Dir  │ 160 B │ 5 months ago
+ 6 │ src    │ Dir  │ 128 B │ 1 day ago
+ 7 │ target │ Dir  │ 160 B │ 5 days ago
+ 8 │ tests  │ Dir  │ 192 B │ 3 months ago
+───┴────────┴──────┴───────┴──────────────
 ```
 
 Because most of the time you'll want to see the output of a pipeline, `autoview` is assumed.
 We could have also written the above:
 
-```
-/home/jonathan/Source/nushell(master)> ls | where type == Directory
+```shell
+> ls | where type == Dir
 ```
 
 Being able to use the same commands and compose them differently is an important philosophy in Nu.
 For example, we could use the built-in `ps` command as well to get a list of the running processes, using the same `where` as above.
 
-```text
-/home/jonathan/Source/nushell(master)> ps | where cpu > 0
-───┬───────┬─────────────────┬──────────┬──────────
- # │ pid   │ name            │ status   │ cpu
-───┼───────┼─────────────────┼──────────┼──────────
- 0 │   992 │ chrome          │ Sleeping │ 6.988768
- 1 │  4240 │ chrome          │ Sleeping │ 5.645982
- 2 │ 13973 │ qemu-system-x86 │ Sleeping │ 4.996551
- 3 │ 15746 │ nu              │ Sleeping │ 84.59905
-───┴───────┴─────────────────┴──────────┴──────────
+```shell
+> ps | where cpu > 0
+───┬────────┬───────────────────┬──────────┬─────────┬──────────┬──────────
+ # │ pid    │ name              │ status   │ cpu     │ mem      │ virtual
+───┼────────┼───────────────────┼──────────┼─────────┼──────────┼──────────
+ 0 │    435 │ irq/142-SYNA327   │ Sleeping │  7.5699 │      0 B │      0 B
+ 1 │   1609 │ pulseaudio        │ Sleeping │  6.5605 │  10.6 MB │   2.3 GB
+ 2 │   1625 │ gnome-shell       │ Sleeping │  6.5684 │ 639.6 MB │   7.3 GB
+ 3 │   2202 │ Web Content       │ Sleeping │  6.8157 │ 320.8 MB │   3.0 GB
+ 4 │ 328788 │ nu_plugin_core_ps │ Sleeping │ 92.5750 │   5.9 MB │ 633.2 MB
+───┴────────┴───────────────────┴──────────┴─────────┴──────────┴──────────
 ```
 
-## Opening files
+### Opening files
 
 Nu can load file and URL contents as raw text or as structured data (if it recognizes the format).
 For example, you can load a .toml file as structured data and explore it:
 
-```
-/home/jonathan/Source/nushell(master)> open Cargo.toml
-──────────────────┬────────────────┬──────────────────
- bin              │ dependencies   │ dev-dependencies
-──────────────────┼────────────────┼──────────────────
- [table: 12 rows] │ [table: 1 row] │ [table: 1 row]
-──────────────────┴────────────────┴──────────────────
+```shell
+> open Cargo.toml
+────────────────────┬───────────────────────────
+ bin                │ [table 18 rows]
+ build-dependencies │ [row serde toml]
+ dependencies       │ [row 29 columns]
+ dev-dependencies   │ [row nu-test-support]
+ features           │ [row 19 columns]
+ package            │ [row 12 columns]
+ workspace          │ [row members]
+────────────────────┴───────────────────────────
 ```
 
 We can pipeline this into a command that gets the contents of one of the columns:
 
-```
-/home/jonathan/Source/nushell(master)> open Cargo.toml | get package
-─────────────────┬────────────────────────────┬─────────┬─────────┬──────┬─────────
- authors         │ description                │ edition │ license │ name │ version
-─────────────────┼────────────────────────────┼─────────┼─────────┼──────┼─────────
- [table: 3 rows] │ A shell for the GitHub era │ 2018    │ MIT     │ nu   │ 0.9.0
-─────────────────┴────────────────────────────┴─────────┴─────────┴──────┴─────────
+```shell
+> open Cargo.toml | get package
+───────────────┬────────────────────────────────────
+ authors       │ [table 1 rows]
+ default-run   │ nu
+ description   │ A new type of shell
+ documentation │ https://www.nushell.sh/book/
+ edition       │ 2018
+ exclude       │ [table 1 rows]
+ homepage      │ https://www.nushell.sh
+ license       │ MIT
+ name          │ nu
+ readme        │ README.md
+ repository    │ https://github.com/nushell/nushell
+ version       │ 0.21.0
+───────────────┴────────────────────────────────────
 ```
 
 Finally, we can use commands outside of Nu once we have the data we want:
 
-```
-/home/jonathan/Source/nushell(master)> open Cargo.toml | get package.version | echo $it
-0.9.0
+```shell
+> open Cargo.toml | get package.version
+0.21.0
 ```
 
 Here we use the variable `$it` to refer to the value being piped to the external command.
 
-## Configuration
+### Configuration
 
-Nu has early support for configuring the shell. It currently supports the following settings:
+Nu has early support for configuring the shell. You can refer to the book for a list of [all supported variables](https://www.nushell.sh/book/en/configuration.html).
 
-| Variable        | Type                 | Description                                                    |
-| --------------- | -------------------- | -------------------------------------------------------------- |
-| path            | table of strings     | PATH to use to find binaries                                   |
-| env             | row                  | the environment variables to pass to external commands         |
-| ctrlc_exit      | boolean              | whether or not to exit Nu after multiple ctrl-c presses        |
-| table_mode      | "light" or other     | enable lightweight or normal tables                            |
-| edit_mode       | "vi" or "emacs"      | changes line editing to "vi" or "emacs" mode                   |
-| completion_mode | "circular" or "list" | changes completion type to "circular" (default) or "list" mode |
+To set one of these variables, you can use `config set`. For example:
 
-To set one of these variables, you can use `config --set`. For example:
-
-```
-> config --set [edit_mode "vi"]
-> config --set [path $nu.path]
+```shell
+> config set edit_mode "vi"
+> config set path $nu.path
 ```
 
-## Shells
+### Shells
 
 Nu will work inside of a single directory and allow you to navigate around your filesystem by default.
 Nu also offers a way of adding additional working directories that you can jump between, allowing you to work in multiple directories at the same time.
@@ -246,7 +254,7 @@ Once you're done with a shell, you can `exit` it and remove it from the ring buf
 
 Finally, to get a list of all the current shells, you can use the `shells` command.
 
-## Plugins
+### Plugins
 
 Nu supports plugins that offer additional functionality to the shell and follow the same structured data model that built-in commands use.
 This allows you to extend nu for your needs.
@@ -258,7 +266,7 @@ These binaries interact with nu via a simple JSON-RPC protocol where the command
 If the plugin is a filter, data streams to it one element at a time, and it can stream data back in return via stdin/stdout.
 If the plugin is a sink, it is given the full vector of final data and is given free reign over stdin/stdout to use as it pleases.
 
-# Goals
+## Goals
 
 Nu adheres closely to a set of goals that make up its design philosophy. As features are added, they are checked against these goals.
 
@@ -272,11 +280,39 @@ Nu adheres closely to a set of goals that make up its design philosophy. As feat
 
 * Finally, Nu views data functionally. Rather than using mutation, pipelines act as a means to load, change, and save data without mutable state.
 
-# Commands
+## Commands
 
 You can find a list of Nu commands, complete with documentation, in [quick command references](https://www.nushell.sh/documentation.html#quick-command-references).
 
-# License
+## Progress
+
+Nu is in heavy development, and will naturally change as it matures and people use it.  The chart below isn't meant to be exhaustive, but rather helps give an idea for some of the areas of development and their relative completion:
+
+| Features | Not started | Prototype | MVP | Preview | Mature | Notes
+| -------- |:-----------:|:---------:|:---:|:-------:|:------:| -----
+| Aliases  |             |     X     |     |         |        | Initial implementation but lacks necessary features
+| Notebook |             |     X     |     |         |        | Initial jupyter support, but it loses state and lacks features
+| File ops |             |           |  X  |         |        | cp, mv, rm, mkdir have some support, but lacking others
+| Environment |          |     X     |     |         |        | Temporary environment, but no session-wide env variables
+| Shells   |             |     X     |     |         |        | Basic value and file shells, but no opt-in/opt-out for commands
+| Protocol |             |           |  X  |         |        | Streaming protocol is serviceable
+| Plugins  |             |     X     |     |         |        | Plugins work on one row at a time, lack batching and expression eval
+| Errors   |             |           |  X  |         |        | Error reporting works, but could use usability polish
+| Documentation |        |     X     |     |         |        | Book and related are barebones and lack task-based lessons
+| Paging   |             |     X     |     |         |        | Textview has paging, but we'd like paging for tables
+| Functions|      X      |           |     |         |        | No functions, yet, only aliases
+| Variables|      X      |           |     |         |        | Nu doesn't yet support variables
+| Completions |          |     X     |     |         |        | Completions are currently barebones, at best
+| Type-checking |        |     X     |     |         |        | Commands check basic types, but input/output isn't checked
+
+## Current Roadmap
+
+We've added a `Roadmap Board` to help collaboratively capture the direction we're going for the current release as well as capture some important issues we'd like to see in Nushell. You can find the Roadmap [here](https://github.com/nushell/nushell/projects/2).
+
+## Contributing
+
+See [Contributing](CONTRIBUTING.md) for details.
+
+## License
 
 The project is made available under the MIT license. See the `LICENSE` file for more information.
-

TODO.md

@@ -1,60 +0,0 @@
-This pattern is extremely repetitive and can be abstracted:
-
-```rs
-    let args = args.evaluate_once(registry)?;
-    let tag = args.name_tag();
-    let input = args.input;
-
-    let stream = async_stream! {
-        let values: Vec<Value> = input.values.collect().await;
-
-        let mut concat_string = String::new();
-        let mut latest_tag: Option<Tag> = None;
-
-        for value in values {
-            latest_tag = Some(value_tag.clone());
-            let value_span = value.tag.span;
-
-            match &value.value {
-                UntaggedValue::Primitive(Primitive::String(s)) => {
-                    concat_string.push_str(&s);
-                    concat_string.push_str("\n");
-                }
-                _ => yield Err(ShellError::labeled_error_with_secondary(
-                    "Expected a string from pipeline",
-                    "requires string input",
-                    name_span,
-                    "value originates from here",
-                    value_span,
-                )),
-
-            }
-        }
-
-```
-
-Mandatory and Optional in parse_command
-
-trace_remaining?
-
-select_fields and select_fields take unnecessary Tag
-
-Value#value should be Value#untagged
-
-Unify dictionary building, probably around a macro
-
-sys plugin in own crate
-
-textview in own crate
-
-Combine atomic and atomic_parse in parser
-
-at_end_possible_ws needs to be comment and separator sensitive
-
-Eliminate unnecessary `nodes` parser
-
-#[derive(HasSpan)]
-
-Figure out a solution for the duplication in stuff like NumberShape vs. NumberExpressionShape
-
-use `struct Expander` from signature.rs

build.rs

@@ -1,3 +0,0 @@
-fn main() -> Result<(), Box<dyn std::error::Error>> {
-    nu_build::build()
-}

crates/nu-build/Cargo.toml

@@ -1,16 +0,0 @@
-[package]
-name = "nu-build"
-version = "0.13.0"
-authors = ["The Nu Project Contributors"]
-edition = "2018"
-description = "Core build system for nushell"
-license = "MIT"
-
-[lib]
-doctest = false
-
-[dependencies]
-serde = { version = "1.0.106", features = ["derive"] }
-lazy_static = "1.4.0"
-serde_json = "1.0.51"
-toml = "0.5.6"

crates/nu-build/src/lib.rs

@@ -1,80 +0,0 @@
-use lazy_static::lazy_static;
-use serde::Deserialize;
-use std::collections::BTreeMap;
-use std::collections::HashMap;
-use std::collections::HashSet;
-use std::env;
-use std::path::{Path, PathBuf};
-use std::sync::Mutex;
-
-lazy_static! {
-    static ref WORKSPACES: Mutex<BTreeMap<String, &'static Path>> = Mutex::new(BTreeMap::new());
-}
-
-// got from https://github.com/mitsuhiko/insta/blob/b113499249584cb650150d2d01ed96ee66db6b30/src/runtime.rs#L67-L88
-
-fn get_cargo_workspace(manifest_dir: &str) -> Result<Option<&Path>, Box<dyn std::error::Error>> {
-    let mut workspaces = WORKSPACES.lock()?;
-    if let Some(rv) = workspaces.get(manifest_dir) {
-        Ok(Some(rv))
-    } else {
-        #[derive(Deserialize)]
-        struct Manifest {
-            workspace_root: String,
-        }
-        let output = std::process::Command::new(env!("CARGO"))
-            .arg("metadata")
-            .arg("--format-version=1")
-            .current_dir(manifest_dir)
-            .output()?;
-        let manifest: Manifest = serde_json::from_slice(&output.stdout)?;
-        let path = Box::leak(Box::new(PathBuf::from(manifest.workspace_root)));
-        workspaces.insert(manifest_dir.to_string(), path.as_path());
-        Ok(workspaces.get(manifest_dir).cloned())
-    }
-}
-
-#[derive(Deserialize)]
-struct Feature {
-    #[allow(unused)]
-    description: String,
-    enabled: bool,
-}
-
-pub fn build() -> Result<(), Box<dyn std::error::Error>> {
-    let input = env::var("CARGO_MANIFEST_DIR")?;
-
-    let all_on = env::var("NUSHELL_ENABLE_ALL_FLAGS").is_ok();
-    let flags: HashSet<String> = env::var("NUSHELL_ENABLE_FLAGS")
-        .map(|s| s.split(',').map(|s| s.to_string()).collect())
-        .unwrap_or_else(|_| HashSet::new());
-
-    if all_on && !flags.is_empty() {
-        println!(
-            "cargo:warning=Both NUSHELL_ENABLE_ALL_FLAGS and NUSHELL_ENABLE_FLAGS were set. You don't need both."
-        );
-    }
-
-    let workspace = match get_cargo_workspace(&input)? {
-        // If the crate is being downloaded from crates.io, it won't have a workspace root, and that's ok
-        None => return Ok(()),
-        Some(workspace) => workspace,
-    };
-
-    let path = Path::new(&workspace).join("features.toml");
-
-    // If the crate is being downloaded from crates.io, it won't have a features.toml, and that's ok
-    if !path.exists() {
-        return Ok(());
-    }
-
-    let toml: HashMap<String, Feature> = toml::from_str(&std::fs::read_to_string(path)?)?;
-
-    for (key, value) in toml.iter() {
-        if value.enabled || all_on || flags.contains(key) {
-            println!("cargo:rustc-cfg={}", key);
-        }
-    }
-
-    Ok(())
-}

crates/nu-cli/Cargo.toml

@@ -1,108 +1,132 @@
 [package]
-name = "nu-cli"
-version = "0.13.0"
 authors = ["The Nu Project Contributors"]
 description = "CLI for nushell"
 edition = "2018"
 license = "MIT"
+name = "nu-cli"
+version = "0.24.0"
+build = "build.rs"
 
 [lib]
 doctest = false
 
 [dependencies]
-nu-source = { version = "0.13.0", path = "../nu-source" }
-nu-plugin = { version = "0.13.0", path = "../nu-plugin" }
-nu-protocol = { version = "0.13.0", path = "../nu-protocol" }
-nu-errors = { version = "0.13.0", path = "../nu-errors" }
-nu-parser = { version = "0.13.0", path = "../nu-parser" }
-nu-value-ext = { version = "0.13.0", path = "../nu-value-ext" }
-nu-test-support = { version = "0.13.0", path = "../nu-test-support" }
+nu-data = {version = "0.24.0", path = "../nu-data"}
+nu-errors = {version = "0.24.0", path = "../nu-errors"}
+nu-json = {version = "0.24.0", path = "../nu-json"}
+nu-parser = {version = "0.24.0", path = "../nu-parser"}
+nu-plugin = {version = "0.24.0", path = "../nu-plugin"}
+nu-protocol = {version = "0.24.0", path = "../nu-protocol"}
+nu-source = {version = "0.24.0", path = "../nu-source"}
+nu-table = {version = "0.24.0", path = "../nu-table"}
+nu-test-support = {version = "0.24.0", path = "../nu-test-support"}
+nu-value-ext = {version = "0.24.0", path = "../nu-value-ext"}
 
 ansi_term = "0.12.1"
-app_dirs = "1.2.1"
-async-stream = "0.2"
-base64 = "0.12.0"
-bigdecimal = { version = "0.1.0", features = ["serde"] }
-bson = { version = "0.14.1", features = ["decimal128"] }
-byte-unit = "3.0.3"
-bytes = "0.5.4"
-calamine = "0.16"
-cfg-if = "0.1"
-chrono = { version = "0.4.11", features = ["serde"] }
-clap = "2.33.0"
-csv = "1.1"
-ctrlc = "3.1.4"
+async-recursion = "0.3.1"
+async-trait = "0.1.40"
+base64 = "0.13.0"
+bigdecimal = {version = "0.2.0", features = ["serde"]}
+byte-unit = "4.0.9"
+bytes = "0.5.6"
+calamine = "0.16.1"
+chrono = {version = "0.4.15", features = ["serde"]}
+chrono-tz = "0.5.3"
+clap = "2.33.3"
+clipboard = {version = "0.5.0", optional = true}
+codespan-reporting = "0.9.5"
+csv = "1.1.3"
+ctrlc = {version = "3.1.6", optional = true}
 derive-new = "0.5.8"
-dirs = "2.0.2"
-dunce = "1.0.0"
+directories = {version = "3.0.1", optional = true}
+dirs = {version = "3.0.1", optional = true}
+dtparse = "1.2.0"
+dunce = "1.0.1"
+eml-parser = "0.1.0"
+encoding_rs = "0.8.24"
 filesize = "0.2.0"
-futures = { version = "0.3", features = ["compat", "io-compat"] }
-futures-util = "0.3.4"
-futures_codec = "0.4"
-getset = "0.1.0"
-git2 = { version = "0.13.1", default_features = false }
+fs_extra = "1.2.0"
+futures = {version = "0.3.5", features = ["compat", "io-compat"]}
+futures_codec = "0.4.1"
+futures-util = "0.3.5"
+getset = "0.1.1"
+git2 = {version = "0.13.11", default_features = false, optional = true}
 glob = "0.3.0"
-hex = "0.4"
+heim = {version = "0.1.0-beta.3", optional = true}
 htmlescape = "0.3.1"
-ical = "0.6.*"
-ichwh = "0.3.4"
-indexmap = { version = "1.3.2", features = ["serde-1"] }
+ical = "0.6.0"
+ichwh = {version = "0.3.4", optional = true}
+indexmap = {version = "1.6.0", features = ["serde-1"]}
+Inflector = "0.11"
 itertools = "0.9.0"
-language-reporting = "0.4.0"
-log = "0.4.8"
-meval = "0.2"
-natural = "0.5.0"
-num-bigint = { version = "0.2.6", features = ["serde"] }
-num-traits = "0.2.11"
-parking_lot = "0.10.0"
-pin-utils = "0.1.0-alpha.4"
-pretty-hex = "0.1.1"
-pretty_env_logger = "0.4.0"
-prettytable-rs = "0.8.0"
-ptree = {version = "0.2" }
+lazy_static = "1.*"
+log = "0.4.11"
+meval = "0.2.0"
+num-bigint = {version = "0.3.0", features = ["serde"]}
+num-format = {version = "0.4.0", features = ["with-num-bigint"]}
+num-traits = "0.2.12"
+parking_lot = "0.11.0"
+pin-utils = "0.1.0"
+pretty-hex = "0.2.0"
+ptree = {version = "0.3.0", optional = true}
 query_interface = "0.3.5"
-rand = "0.7"
-regex = "1"
-roxmltree = "0.10.1"
-rustyline = "6.1.1"
-serde = { version = "1.0.106", features = ["derive"] }
-serde-hjson = "0.9.1"
-serde_bytes = "0.11.3"
+quick-xml = "0.18.1"
+rand = "0.7.3"
+rayon = "1.4.0"
+regex = "1.3.9"
+roxmltree = "0.13.0"
+rust-embed = "5.6.0"
+rustyline = {version = "6.3.0", optional = true}
+serde = {version = "1.0.115", features = ["derive"]}
+serde_bytes = "0.11.5"
 serde_ini = "0.2.0"
-serde_json = "1.0.51"
-serde_urlencoded = "0.6.1"
-serde_yaml = "0.8"
+serde_json = "1.0.57"
+serde_urlencoded = "0.7.0"
+serde_yaml = "0.8.13"
+sha2 = "0.9.1"
 shellexpand = "2.0.0"
 strip-ansi-escapes = "0.1.0"
+sxd-document = "0.3.2"
+sxd-xpath = "0.4.2"
 tempfile = "3.1.0"
-term = "0.5.2"
+term = {version = "0.6.1", optional = true}
+term_size = "0.3.2"
 termcolor = "1.1.0"
-textwrap = {version = "0.11.0", features = ["term_size"]}
+titlecase = "1.0"
 toml = "0.5.6"
-typetag = "0.1.4"
-umask = "0.1"
-unicode-xid = "0.2.0"
-
-trash = { version = "1.0.0", optional = true }
-clipboard = { version = "0.5", optional = true }
-starship = { version = "0.39.0", optional = true }
+trash = {version = "1.2.0", optional = true}
+unicode-segmentation = "1.6.0"
+uom = {version = "0.28.0", features = ["f64", "try-from"]}
+url = "2.1.1"
+uuid_crate = {package = "uuid", version = "0.8.1", features = ["v4"], optional = true}
+which = {version = "4.0.2", optional = true}
+zip = {version = "0.5.7", optional = true}
 
 [target.'cfg(unix)'.dependencies]
+umask = "1.0.0"
 users = "0.10.0"
 
+# TODO this will be possible with new dependency resolver
+#   (currently on nightly behind -Zfeatures=itarget):
+#   https://github.com/rust-lang/cargo/issues/7914
+#[target.'cfg(not(windows))'.dependencies]
+#num-format = {version = "0.4", features = ["with-system-locale"]}
+
 [dependencies.rusqlite]
-version = "0.22.0"
 features = ["bundled", "blob"]
+optional = true
+version = "0.24.0"
 
 [build-dependencies]
-nu-build = { version = "0.13.0", path = "../nu-build" }
+shadow-rs = "0.3.20"
 
 [dev-dependencies]
-quickcheck = "0.9"
-quickcheck_macros = "0.9"
+quickcheck = "0.9.2"
+quickcheck_macros = "0.9.1"
 
 [features]
-stable = []
-starship-prompt = ["starship"]
 clipboard-cli = ["clipboard"]
+rich-benchmark = ["heim"]
+rustyline-support = ["rustyline"]
+stable = []
 trash-support = ["trash"]

crates/nu-cli/build.rs

@@ -0,0 +1,6 @@
+fn main() -> shadow_rs::SdResult<()> {
+    let src_path = std::env::var("CARGO_MANIFEST_DIR")?;
+    let out_path = std::env::var("OUT_DIR")?;
+    shadow_rs::Shadow::build(src_path, out_path)?;
+    Ok(())
+}

crates/nu-cli/src/command_registry.rs

@@ -0,0 +1,64 @@
+use crate::commands::Command;
+use indexmap::IndexMap;
+use nu_errors::ShellError;
+use nu_parser::SignatureRegistry;
+use nu_protocol::Signature;
+use parking_lot::Mutex;
+use std::sync::Arc;
+
+#[derive(Debug, Clone, Default)]
+pub struct CommandRegistry {
+    registry: Arc<Mutex<IndexMap<String, Command>>>,
+}
+
+impl SignatureRegistry for CommandRegistry {
+    fn has(&self, name: &str) -> bool {
+        let registry = self.registry.lock();
+        registry.contains_key(name)
+    }
+    fn get(&self, name: &str) -> Option<Signature> {
+        let registry = self.registry.lock();
+        registry.get(name).map(|command| command.signature())
+    }
+    fn clone_box(&self) -> Box<dyn SignatureRegistry> {
+        Box::new(self.clone())
+    }
+}
+
+impl CommandRegistry {
+    pub fn new() -> CommandRegistry {
+        CommandRegistry {
+            registry: Arc::new(Mutex::new(IndexMap::default())),
+        }
+    }
+}
+
+impl CommandRegistry {
+    pub fn get_command(&self, name: &str) -> Option<Command> {
+        let registry = self.registry.lock();
+
+        registry.get(name).cloned()
+    }
+
+    pub fn expect_command(&self, name: &str) -> Result<Command, ShellError> {
+        self.get_command(name).ok_or_else(|| {
+            ShellError::untagged_runtime_error(format!("Could not load command: {}", name))
+        })
+    }
+
+    pub fn has(&self, name: &str) -> bool {
+        let registry = self.registry.lock();
+
+        registry.contains_key(name)
+    }
+
+    pub fn insert(&mut self, name: impl Into<String>, command: Command) {
+        let mut registry = self.registry.lock();
+        registry.insert(name.into(), command);
+    }
+
+    pub fn names(&self) -> Vec<String> {
+        let registry = self.registry.lock();
+        registry.keys().cloned().collect()
+    }
+}

crates/nu-cli/src/commands.rs

@@ -5,38 +5,52 @@ mod from_delimited_data;
 mod to_delimited_data;
 
 pub(crate) mod alias;
+pub(crate) mod ansi;
 pub(crate) mod append;
 pub(crate) mod args;
+pub(crate) mod autoenv;
+pub(crate) mod autoenv_trust;
+pub(crate) mod autoenv_untrust;
 pub(crate) mod autoview;
-pub(crate) mod calc;
+pub(crate) mod benchmark;
+pub(crate) mod build_string;
+pub(crate) mod cal;
 pub(crate) mod cd;
+pub(crate) mod char_;
+pub(crate) mod chart;
 pub(crate) mod classified;
+#[cfg(feature = "clipboard-cli")]
 pub(crate) mod clip;
 pub(crate) mod command;
 pub(crate) mod compact;
 pub(crate) mod config;
+pub(crate) mod constants;
 pub(crate) mod count;
 pub(crate) mod cp;
 pub(crate) mod date;
 pub(crate) mod debug;
 pub(crate) mod default;
+pub(crate) mod describe;
+pub(crate) mod do_;
+pub(crate) mod drop;
 pub(crate) mod du;
 pub(crate) mod each;
 pub(crate) mod echo;
-pub(crate) mod edit;
+pub(crate) mod empty;
 pub(crate) mod enter;
-#[allow(unused)]
-pub(crate) mod evaluate_by;
+pub(crate) mod every;
+pub(crate) mod exec;
 pub(crate) mod exit;
 pub(crate) mod first;
+pub(crate) mod flatten;
 pub(crate) mod format;
-pub(crate) mod from_bson;
+pub(crate) mod from;
 pub(crate) mod from_csv;
+pub(crate) mod from_eml;
 pub(crate) mod from_ics;
 pub(crate) mod from_ini;
 pub(crate) mod from_json;
 pub(crate) mod from_ods;
-pub(crate) mod from_sqlite;
 pub(crate) mod from_ssv;
 pub(crate) mod from_toml;
 pub(crate) mod from_tsv;
@@ -47,31 +61,36 @@ pub(crate) mod from_xml;
 pub(crate) mod from_yaml;
 pub(crate) mod get;
 pub(crate) mod group_by;
+pub(crate) mod group_by_date;
+pub(crate) mod hash_;
 pub(crate) mod headers;
 pub(crate) mod help;
 pub(crate) mod histogram;
 pub(crate) mod history;
+pub(crate) mod if_;
 pub(crate) mod insert;
+pub(crate) mod into_int;
+pub(crate) mod keep;
 pub(crate) mod last;
 pub(crate) mod lines;
 pub(crate) mod ls;
-#[allow(unused)]
-pub(crate) mod map_max_by;
+pub(crate) mod math;
+pub(crate) mod merge;
 pub(crate) mod mkdir;
-pub(crate) mod mv;
+pub(crate) mod move_;
 pub(crate) mod next;
 pub(crate) mod nth;
+pub(crate) mod nu;
 pub(crate) mod open;
 pub(crate) mod parse;
-pub(crate) mod pick;
+pub(crate) mod path;
 pub(crate) mod pivot;
-pub(crate) mod plugin;
 pub(crate) mod prepend;
 pub(crate) mod prev;
 pub(crate) mod pwd;
+pub(crate) mod random;
 pub(crate) mod range;
-#[allow(unused)]
-pub(crate) mod reduce_by;
+pub(crate) mod reduce;
 pub(crate) mod reject;
 pub(crate) mod rename;
 pub(crate) mod reverse;
@@ -79,78 +98,96 @@ pub(crate) mod rm;
 pub(crate) mod run_alias;
 pub(crate) mod run_external;
 pub(crate) mod save;
+pub(crate) mod select;
+pub(crate) mod seq;
+pub(crate) mod seq_dates;
 pub(crate) mod shells;
 pub(crate) mod shuffle;
 pub(crate) mod size;
 pub(crate) mod skip;
-pub(crate) mod skip_while;
+pub(crate) mod sleep;
 pub(crate) mod sort_by;
+pub(crate) mod split;
 pub(crate) mod split_by;
-pub(crate) mod split_column;
-pub(crate) mod split_row;
-pub(crate) mod sum;
-#[allow(unused)]
-pub(crate) mod t_sort_by;
+pub(crate) mod str_;
 pub(crate) mod table;
 pub(crate) mod tags;
-pub(crate) mod to_bson;
+pub(crate) mod to;
 pub(crate) mod to_csv;
 pub(crate) mod to_html;
 pub(crate) mod to_json;
 pub(crate) mod to_md;
-pub(crate) mod to_sqlite;
 pub(crate) mod to_toml;
 pub(crate) mod to_tsv;
 pub(crate) mod to_url;
+pub(crate) mod to_xml;
 pub(crate) mod to_yaml;
-pub(crate) mod trim;
 pub(crate) mod uniq;
+pub(crate) mod update;
+pub(crate) mod url_;
 pub(crate) mod version;
-pub(crate) mod what;
 pub(crate) mod where_;
 pub(crate) mod which_;
+pub(crate) mod with_env;
 pub(crate) mod wrap;
 
 pub(crate) use autoview::Autoview;
 pub(crate) use cd::Cd;
 pub(crate) use command::{
-    per_item_command, whole_stream_command, Command, PerItemCommand, UnevaluatedCallInfo,
-    WholeStreamCommand,
+    whole_stream_command, Command, Example, UnevaluatedCallInfo, WholeStreamCommand,
 };
 
 pub(crate) use alias::Alias;
-pub(crate) use append::Append;
-pub(crate) use calc::Calc;
+pub(crate) use ansi::Ansi;
+pub(crate) use append::Command as Append;
+pub(crate) use autoenv::Autoenv;
+pub(crate) use autoenv_trust::AutoenvTrust;
+pub(crate) use autoenv_untrust::AutoenvUnTrust;
+pub(crate) use benchmark::Benchmark;
+pub(crate) use build_string::BuildString;
+pub(crate) use cal::Cal;
+pub(crate) use char_::Char;
+pub(crate) use chart::Chart;
 pub(crate) use compact::Compact;
-pub(crate) use config::Config;
+pub(crate) use config::{
+    Config, ConfigClear, ConfigGet, ConfigLoad, ConfigPath, ConfigRemove, ConfigSet, ConfigSetInto,
+};
 pub(crate) use count::Count;
 pub(crate) use cp::Cpy;
-pub(crate) use date::Date;
+pub(crate) use date::{Date, DateFormat, DateListTimeZone, DateNow, DateToTable, DateToTimeZone};
 pub(crate) use debug::Debug;
 pub(crate) use default::Default;
+pub(crate) use describe::Describe;
+pub(crate) use do_::Do;
+pub(crate) use drop::Drop;
 pub(crate) use du::Du;
 pub(crate) use each::Each;
+pub(crate) use each::EachGroup;
+pub(crate) use each::EachWindow;
 pub(crate) use echo::Echo;
-pub(crate) use edit::Edit;
+pub(crate) use empty::Command as Empty;
+pub(crate) use if_::If;
+pub(crate) use nu::NuPlugin;
+pub(crate) use update::Command as Update;
 pub(crate) mod kill;
 pub(crate) use kill::Kill;
 pub(crate) mod clear;
 pub(crate) use clear::Clear;
 pub(crate) mod touch;
 pub(crate) use enter::Enter;
-#[allow(unused_imports)]
-pub(crate) use evaluate_by::EvaluateBy;
+pub(crate) use every::Every;
+pub(crate) use exec::Exec;
 pub(crate) use exit::Exit;
 pub(crate) use first::First;
-pub(crate) use format::Format;
-pub(crate) use from_bson::FromBSON;
+pub(crate) use flatten::Command as Flatten;
+pub(crate) use format::{FileSize, Format};
+pub(crate) use from::From;
 pub(crate) use from_csv::FromCSV;
+pub(crate) use from_eml::FromEML;
 pub(crate) use from_ics::FromIcs;
 pub(crate) use from_ini::FromINI;
 pub(crate) use from_json::FromJSON;
 pub(crate) use from_ods::FromODS;
-pub(crate) use from_sqlite::FromDB;
-pub(crate) use from_sqlite::FromSQLite;
 pub(crate) use from_ssv::FromSSV;
 pub(crate) use from_toml::FromTOML;
 pub(crate) use from_tsv::FromTSV;
@@ -161,67 +198,128 @@ pub(crate) use from_xml::FromXML;
 pub(crate) use from_yaml::FromYAML;
 pub(crate) use from_yaml::FromYML;
 pub(crate) use get::Get;
-pub(crate) use group_by::GroupBy;
+pub(crate) use group_by::Command as GroupBy;
+pub(crate) use group_by_date::GroupByDate;
+pub(crate) use hash_::{Hash, HashBase64};
 pub(crate) use headers::Headers;
 pub(crate) use help::Help;
 pub(crate) use histogram::Histogram;
 pub(crate) use history::History;
-pub(crate) use insert::Insert;
+pub(crate) use insert::Command as Insert;
+pub(crate) use into_int::IntoInt;
+pub(crate) use keep::{Keep, KeepUntil, KeepWhile};
 pub(crate) use last::Last;
 pub(crate) use lines::Lines;
 pub(crate) use ls::Ls;
-#[allow(unused_imports)]
-pub(crate) use map_max_by::MapMaxBy;
+pub(crate) use math::{
+    Math, MathAbs, MathAverage, MathCeil, MathEval, MathFloor, MathMaximum, MathMedian,
+    MathMinimum, MathMode, MathProduct, MathRound, MathStddev, MathSummation, MathVariance,
+};
+pub(crate) use merge::Merge;
 pub(crate) use mkdir::Mkdir;
-pub(crate) use mv::Move;
+pub(crate) use move_::{Move, Mv};
 pub(crate) use next::Next;
 pub(crate) use nth::Nth;
 pub(crate) use open::Open;
 pub(crate) use parse::Parse;
-pub(crate) use pick::Pick;
+pub(crate) use path::{
+    PathBasename, PathCommand, PathDirname, PathExists, PathExpand, PathExtension, PathFilestem,
+    PathType,
+};
 pub(crate) use pivot::Pivot;
 pub(crate) use prepend::Prepend;
 pub(crate) use prev::Previous;
 pub(crate) use pwd::Pwd;
+#[cfg(feature = "uuid_crate")]
+pub(crate) use random::RandomUUID;
+pub(crate) use random::{
+    Random, RandomBool, RandomChars, RandomDecimal, RandomDice, RandomInteger,
+};
 pub(crate) use range::Range;
-#[allow(unused_imports)]
-pub(crate) use reduce_by::ReduceBy;
+pub(crate) use reduce::Reduce;
 pub(crate) use reject::Reject;
 pub(crate) use rename::Rename;
 pub(crate) use reverse::Reverse;
 pub(crate) use rm::Remove;
 pub(crate) use run_external::RunExternalCommand;
 pub(crate) use save::Save;
+pub(crate) use select::Select;
+pub(crate) use seq::Seq;
+pub(crate) use seq_dates::SeqDates;
 pub(crate) use shells::Shells;
 pub(crate) use shuffle::Shuffle;
 pub(crate) use size::Size;
-pub(crate) use skip::Skip;
-pub(crate) use skip_while::SkipWhile;
+pub(crate) use skip::{Skip, SkipUntil, SkipWhile};
+pub(crate) use sleep::Sleep;
 pub(crate) use sort_by::SortBy;
+pub(crate) use split::{Split, SplitChars, SplitColumn, SplitRow};
 pub(crate) use split_by::SplitBy;
-pub(crate) use split_column::SplitColumn;
-pub(crate) use split_row::SplitRow;
-pub(crate) use sum::Sum;
-#[allow(unused_imports)]
-pub(crate) use t_sort_by::TSortBy;
+pub(crate) use str_::{
+    Str, StrCamelCase, StrCapitalize, StrCollect, StrContains, StrDowncase, StrEndsWith,
+    StrFindReplace, StrFrom, StrIndexOf, StrKebabCase, StrLPad, StrLength, StrPascalCase, StrRPad,
+    StrReverse, StrScreamingSnakeCase, StrSet, StrSnakeCase, StrStartsWith, StrSubstring,
+    StrToDatetime, StrToDecimal, StrToInteger, StrTrim, StrTrimLeft, StrTrimRight, StrUpcase,
+};
 pub(crate) use table::Table;
 pub(crate) use tags::Tags;
-pub(crate) use to_bson::ToBSON;
+pub(crate) use to::To;
 pub(crate) use to_csv::ToCSV;
 pub(crate) use to_html::ToHTML;
 pub(crate) use to_json::ToJSON;
 pub(crate) use to_md::ToMarkdown;
-pub(crate) use to_sqlite::ToDB;
-pub(crate) use to_sqlite::ToSQLite;
 pub(crate) use to_toml::ToTOML;
 pub(crate) use to_tsv::ToTSV;
 pub(crate) use to_url::ToURL;
+pub(crate) use to_xml::ToXML;
 pub(crate) use to_yaml::ToYAML;
 pub(crate) use touch::Touch;
-pub(crate) use trim::Trim;
 pub(crate) use uniq::Uniq;
+pub(crate) use url_::{UrlCommand, UrlHost, UrlPath, UrlQuery, UrlScheme};
 pub(crate) use version::Version;
-pub(crate) use what::What;
 pub(crate) use where_::Where;
 pub(crate) use which_::Which;
+pub(crate) use with_env::WithEnv;
 pub(crate) use wrap::Wrap;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::commands::whole_stream_command;
+    use crate::examples::{test_anchors, test_examples};
+    use nu_errors::ShellError;
+
+    fn full_tests() -> Vec<Command> {
+        vec![
+            whole_stream_command(Append),
+            whole_stream_command(GroupBy),
+            whole_stream_command(Insert),
+            whole_stream_command(Move),
+            whole_stream_command(Update),
+            whole_stream_command(Empty),
+        ]
+    }
+
+    fn only_examples() -> Vec<Command> {
+        let mut commands = full_tests();
+        commands.extend(vec![whole_stream_command(Flatten)]);
+        commands
+    }
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        for cmd in only_examples() {
+            test_examples(cmd)?;
+        }
+
+        Ok(())
+    }
+
+    #[test]
+    fn tracks_metadata() -> Result<(), ShellError> {
+        for cmd in full_tests() {
+            test_anchors(cmd)?;
+        }
+
+        Ok(())
+    }
+}

crates/nu-cli/src/commands/alias.rs

@@ -1,14 +1,30 @@
-use crate::commands::PerItemCommand;
-use crate::context::CommandRegistry;
+use crate::command_registry::CommandRegistry;
+use crate::commands::WholeStreamCommand;
 use crate::prelude::*;
+
+use crate::types::deduction::{VarDeclaration, VarSyntaxShapeDeductor};
+use deduction_to_signature::DeductionToSignature;
+use log::trace;
+use nu_data::config;
 use nu_errors::ShellError;
 use nu_protocol::{
-    CallInfo, CommandAction, Primitive, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value,
+    hir::Block, CommandAction, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value,
 };
+use nu_source::Tagged;
 
 pub struct Alias;
 
-impl PerItemCommand for Alias {
+#[derive(Deserialize)]
+pub struct AliasArgs {
+    pub name: Tagged<String>,
+    pub args: Vec<Value>,
+    pub block: Block,
+    pub infer: Option<bool>,
+    pub save: Option<bool>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for Alias {
     fn name(&self) -> &str {
         "alias"
     }
@@ -17,49 +33,189 @@ impl PerItemCommand for Alias {
         Signature::build("alias")
             .required("name", SyntaxShape::String, "the name of the alias")
             .required("args", SyntaxShape::Table, "the arguments to the alias")
-            .required("block", SyntaxShape::Block, "the block to run on each row")
+            .required(
+                "block",
+                SyntaxShape::Block,
+                "the block to run as the body of the alias",
+            )
+            .switch("infer", "infer argument types (experimental)", Some('i'))
+            .switch("save", "save the alias to your config", Some('s'))
     }
 
     fn usage(&self) -> &str {
-        "Run a block on each row of the table."
+        "Define a shortcut for another command."
     }
 
-    fn run(
+    async fn run(
         &self,
-        call_info: &CallInfo,
-        _registry: &CommandRegistry,
-        _raw_args: &RawCommandArgs,
-        _input: Value,
+        args: CommandArgs,
+        registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
-        let call_info = call_info.clone();
-        let stream = async_stream! {
-            match (call_info.args.expect_nth(0)?, call_info.args.expect_nth(1)?, call_info.args.expect_nth(2)?) {
-                (Value {value: UntaggedValue::Primitive(Primitive::String(name)), .. },
-                Value { value: UntaggedValue::Table(list), .. },
-                Value {
-                    value: UntaggedValue::Block(block),
-                    tag
-                }) => {
-                    let mut args: Vec<String> = vec![];
-                    for item in list.iter() {
-                        if let Ok(string) = item.as_string() {
-                            args.push(format!("${}", string));
-                        } else {
-                            yield Err(ShellError::labeled_error("Expected a string", "expected a string", item.tag()));
-                        }
-                    }
-                    yield ReturnSuccess::action(CommandAction::AddAlias(name.to_string(), args, block.clone()))
-                }
-                _ => {
-                    yield Err(ShellError::labeled_error(
-                        "Expected `name [args] {block}",
-                        "needs a name, args, and a block",
-                        call_info.name_tag,
-                    ))
-                }
-            };
-        };
+        alias(args, registry).await
+    }
 
-        Ok(stream.to_output_stream())
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "An alias without parameters",
+                example: "alias say-hi [] { echo 'Hello!' }",
+                result: None,
+            },
+            Example {
+                description: "An alias with a single parameter",
+                example: "alias l [x] { ls $x }",
+                result: None,
+            },
+        ]
+    }
+}
+
+pub async fn alias(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+    let mut raw_input = args.raw_input.clone();
+    let (
+        AliasArgs {
+            name,
+            args: list,
+            block,
+            infer,
+            save,
+        },
+        _ctx,
+    ) = args.process(&registry).await?;
+
+    if let Some(true) = save {
+        let mut result = nu_data::config::read(name.clone().tag, &None)?;
+
+        // process the alias to remove the --save flag
+        let left_brace = raw_input.find('{').unwrap_or(0);
+        let right_brace = raw_input.rfind('}').unwrap_or_else(|| raw_input.len());
+        let left = raw_input[..left_brace]
+            .replace("--save", "") // TODO using regex (or reconstruct string from AST?)
+            .replace("-si", "-i")
+            .replace("-s ", "")
+            .replace("-is", "-i");
+        let right = raw_input[right_brace..]
+            .replace("--save", "")
+            .replace("-si", "-i")
+            .replace("-s ", "")
+            .replace("-is", "-i");
+        raw_input = format!("{}{}{}", left, &raw_input[left_brace..right_brace], right);
+
+        // create a value from raw_input alias
+        let alias: Value = raw_input.trim().to_string().into();
+        let alias_start = raw_input.find('[').unwrap_or(0); // used to check if the same alias already exists
+
+        // add to startup if alias doesn't exist and replace if it does
+        match result.get_mut("startup") {
+            Some(startup) => {
+                if let UntaggedValue::Table(ref mut commands) = startup.value {
+                    if let Some(command) = commands.iter_mut().find(|command| {
+                        let cmd_str = command.as_string().unwrap_or_default();
+                        cmd_str.starts_with(&raw_input[..alias_start])
+                    }) {
+                        *command = alias;
+                    } else {
+                        commands.push(alias);
+                    }
+                }
+            }
+            None => {
+                let table = UntaggedValue::table(&[alias]);
+                result.insert("startup".to_string(), table.into_value(Tag::default()));
+            }
+        }
+        config::write(&result, &None)?;
+    }
+
+    let mut processed_args: Vec<VarDeclaration> = vec![];
+    for (_, item) in list.iter().enumerate() {
+        match item.as_string() {
+            Ok(var_name) => {
+                let dollar_var_name = format!("${}", var_name);
+                processed_args.push(VarDeclaration {
+                    name: dollar_var_name,
+                    // type_decl: None,
+                    span: item.tag.span,
+                });
+            }
+            Err(_) => {
+                return Err(ShellError::labeled_error(
+                    "Expected a string",
+                    "expected a string",
+                    item.tag(),
+                ));
+            }
+        }
+    }
+    trace!("Found vars: {:?}", processed_args);
+
+    let inferred_shapes = {
+        if let Some(true) = infer {
+            VarSyntaxShapeDeductor::infer_vars(&processed_args, &block, &registry)?
+        } else {
+            processed_args.into_iter().map(|arg| (arg, None)).collect()
+        }
+    };
+    let signature = DeductionToSignature::get(&name.item, &inferred_shapes);
+    trace!("Inferred signature: {:?}", signature);
+
+    Ok(OutputStream::one(ReturnSuccess::action(
+        CommandAction::AddAlias(Box::new(signature), block),
+    )))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Alias;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Alias {})?)
+    }
+}
+
+mod deduction_to_signature {
+    //For now this logic is relativly simple.
+    //For each var, one mandatory positional is added.
+    //As soon as more support for optional positional arguments is arrived,
+    //this logic might be a little bit more tricky.
+    use crate::types::deduction::{Deduction, VarDeclaration};
+    use nu_protocol::{PositionalType, Signature, SyntaxShape};
+
+    pub struct DeductionToSignature {}
+    impl DeductionToSignature {
+        pub fn get(
+            cmd_name: &str,
+            deductions: &[(VarDeclaration, Option<Deduction>)],
+        ) -> Signature {
+            let mut signature = Signature::build(cmd_name);
+            for (decl, deduction) in deductions {
+                match deduction {
+                    None => signature.positional.push((
+                        PositionalType::optional(&decl.name, SyntaxShape::Any),
+                        decl.name.clone(),
+                    )),
+                    Some(deduction) => match deduction {
+                        Deduction::VarShapeDeduction(normal_var_deduction) => {
+                            signature.positional.push((
+                                PositionalType::optional(
+                                    &decl.name,
+                                    normal_var_deduction[0].deduction,
+                                ),
+                                decl.name.clone(),
+                            ))
+                        }
+                    },
+                }
+            }
+            signature
+        }
     }
 }

crates/nu-cli/src/commands/ansi.rs

@@ -0,0 +1,244 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use ansi_term::Color;
+use nu_errors::ShellError;
+use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
+use nu_source::Tagged;
+
+pub struct Ansi;
+
+#[derive(Deserialize)]
+struct AnsiArgs {
+    color: Value,
+    escape: Option<Tagged<String>>,
+    osc: Option<Tagged<String>>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for Ansi {
+    fn name(&self) -> &str {
+        "ansi"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("ansi")
+            .optional(
+                "color",
+                SyntaxShape::Any,
+                "the name of the color to use or 'reset' to reset the color",
+            )
+            .named(
+                "escape", // \x1b
+                SyntaxShape::Any,
+                "escape sequence without the escape character(s)",
+                Some('e'),
+            )
+            .named(
+                "osc",
+                SyntaxShape::Any,
+                "operating system command (ocs) escape sequence without the escape character(s)",
+                Some('o'),
+            )
+    }
+
+    fn usage(&self) -> &str {
+        r#"Output ANSI codes to change color
+
+For escape sequences:
+Escape: '\x1b[' is not required for --escape parameter
+Format: #(;#)m
+Example: 1;31m for bold red or 2;37;41m for dimmed white fg with red bg
+There can be multiple text formatting sequence numbers
+separated by a ; and ending with an m where the # is of the
+following values:
+    attributes
+    0    reset / normal display
+    1    bold or increased intensity
+    2    faint or decreased intensity
+    3    italic on (non-mono font)
+    4    underline on
+    5    slow blink on
+    6    fast blink on
+    7    reverse video on
+    8    nondisplayed (invisible) on
+    9    strike-through on
+
+    foreground/bright colors    background/bright colors
+    30/90    black              40/100    black
+    31/91    red                41/101    red
+    32/92    green              42/102    green
+    33/93    yellow             43/103    yellow
+    34/94    blue               44/104    blue
+    35/95    magenta            45/105    magenta
+    36/96    cyan               46/106    cyan
+    37/97    white              47/107    white
+    https://en.wikipedia.org/wiki/ANSI_escape_code
+
+OSC: '\x1b]' is not required for --osc parameter
+Example: echo [$(ansi -o '0') 'some title' $(char bel)] | str collect
+Format: #
+    0 Set window title and icon name
+    1 Set icon name
+    2 Set window title
+    4 Set/read color palette
+    9 iTerm2 Grown notifications
+    10 Set foreground color (x11 color spec)
+    11 Set background color (x11 color spec)
+    ... others"#
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Change color to green",
+                example: r#"ansi green"#,
+                result: Some(vec![Value::from("\u{1b}[32m")]),
+            },
+            Example {
+                description: "Reset the color",
+                example: r#"ansi reset"#,
+                result: Some(vec![Value::from("\u{1b}[0m")]),
+            },
+            Example {
+                description:
+                    "Use ansi to color text (rb = red bold, gb = green bold, pb = purple bold)",
+                example: r#"echo [$(ansi rb) Hello " " $(ansi gb) Nu " " $(ansi pb) World] | str collect"#,
+                result: Some(vec![Value::from(
+                    "\u{1b}[1;31mHello \u{1b}[1;32mNu \u{1b}[1;35mWorld",
+                )]),
+            },
+            Example {
+                description:
+                    "Use ansi to color text (rb = red bold, gb = green bold, pb = purple bold)",
+                example: r#"echo [$(ansi -e '3;93;41m') Hello $(ansi reset) " " $(ansi gb) Nu " " $(ansi pb) World] | str collect"#,
+                result: Some(vec![Value::from(
+                    "\u{1b}[3;93;41mHello\u{1b}[0m \u{1b}[1;32mNu \u{1b}[1;35mWorld",
+                )]),
+            },
+        ]
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        let (AnsiArgs { color, escape, osc }, _) = args.process(&registry).await?;
+
+        if let Some(e) = escape {
+            let esc_vec: Vec<char> = e.item.chars().collect();
+            if esc_vec[0] == '\\' {
+                return Err(ShellError::labeled_error(
+                    "no need for escape characters",
+                    "no need for escape characters",
+                    e.tag(),
+                ));
+            }
+            let output = format!("\x1b[{}", e.item);
+            return Ok(OutputStream::one(ReturnSuccess::value(
+                UntaggedValue::string(output).into_value(e.tag()),
+            )));
+        }
+
+        if let Some(o) = osc {
+            let osc_vec: Vec<char> = o.item.chars().collect();
+            if osc_vec[0] == '\\' {
+                return Err(ShellError::labeled_error(
+                    "no need for escape characters",
+                    "no need for escape characters",
+                    o.tag(),
+                ));
+            }
+            //Operating system command aka osc  ESC ] <- note the right brace, not left brace for osc
+            // OCS's need to end with a bell '\x07' char
+            let output = format!("\x1b]{};", o.item);
+            return Ok(OutputStream::one(ReturnSuccess::value(
+                UntaggedValue::string(output).into_value(o.tag()),
+            )));
+        }
+
+        let color_string = color.as_string()?;
+        let ansi_code = str_to_ansi_color(color_string);
+
+        if let Some(output) = ansi_code {
+            Ok(OutputStream::one(ReturnSuccess::value(
+                UntaggedValue::string(output).into_value(color.tag()),
+            )))
+        } else {
+            Err(ShellError::labeled_error(
+                "Unknown color",
+                "unknown color",
+                color.tag(),
+            ))
+        }
+        // }
+    }
+}
+
+pub fn str_to_ansi_color(s: String) -> Option<String> {
+    match s.as_str() {
+        "g" | "green" => Some(Color::Green.prefix().to_string()),
+        "gb" | "green_bold" => Some(Color::Green.bold().prefix().to_string()),
+        "gu" | "green_underline" => Some(Color::Green.underline().prefix().to_string()),
+        "gi" | "green_italic" => Some(Color::Green.italic().prefix().to_string()),
+        "gd" | "green_dimmed" => Some(Color::Green.dimmed().prefix().to_string()),
+        "gr" | "green_reverse" => Some(Color::Green.reverse().prefix().to_string()),
+        "r" | "red" => Some(Color::Red.prefix().to_string()),
+        "rb" | "red_bold" => Some(Color::Red.bold().prefix().to_string()),
+        "ru" | "red_underline" => Some(Color::Red.underline().prefix().to_string()),
+        "ri" | "red_italic" => Some(Color::Red.italic().prefix().to_string()),
+        "rd" | "red_dimmed" => Some(Color::Red.dimmed().prefix().to_string()),
+        "rr" | "red_reverse" => Some(Color::Red.reverse().prefix().to_string()),
+        "u" | "blue" => Some(Color::Blue.prefix().to_string()),
+        "ub" | "blue_bold" => Some(Color::Blue.bold().prefix().to_string()),
+        "uu" | "blue_underline" => Some(Color::Blue.underline().prefix().to_string()),
+        "ui" | "blue_italic" => Some(Color::Blue.italic().prefix().to_string()),
+        "ud" | "blue_dimmed" => Some(Color::Blue.dimmed().prefix().to_string()),
+        "ur" | "blue_reverse" => Some(Color::Blue.reverse().prefix().to_string()),
+        "b" | "black" => Some(Color::Black.prefix().to_string()),
+        "bb" | "black_bold" => Some(Color::Black.bold().prefix().to_string()),
+        "bu" | "black_underline" => Some(Color::Black.underline().prefix().to_string()),
+        "bi" | "black_italic" => Some(Color::Black.italic().prefix().to_string()),
+        "bd" | "black_dimmed" => Some(Color::Black.dimmed().prefix().to_string()),
+        "br" | "black_reverse" => Some(Color::Black.reverse().prefix().to_string()),
+        "y" | "yellow" => Some(Color::Yellow.prefix().to_string()),
+        "yb" | "yellow_bold" => Some(Color::Yellow.bold().prefix().to_string()),
+        "yu" | "yellow_underline" => Some(Color::Yellow.underline().prefix().to_string()),
+        "yi" | "yellow_italic" => Some(Color::Yellow.italic().prefix().to_string()),
+        "yd" | "yellow_dimmed" => Some(Color::Yellow.dimmed().prefix().to_string()),
+        "yr" | "yellow_reverse" => Some(Color::Yellow.reverse().prefix().to_string()),
+        "p" | "purple" => Some(Color::Purple.prefix().to_string()),
+        "pb" | "purple_bold" => Some(Color::Purple.bold().prefix().to_string()),
+        "pu" | "purple_underline" => Some(Color::Purple.underline().prefix().to_string()),
+        "pi" | "purple_italic" => Some(Color::Purple.italic().prefix().to_string()),
+        "pd" | "purple_dimmed" => Some(Color::Purple.dimmed().prefix().to_string()),
+        "pr" | "purple_reverse" => Some(Color::Purple.reverse().prefix().to_string()),
+        "c" | "cyan" => Some(Color::Cyan.prefix().to_string()),
+        "cb" | "cyan_bold" => Some(Color::Cyan.bold().prefix().to_string()),
+        "cu" | "cyan_underline" => Some(Color::Cyan.underline().prefix().to_string()),
+        "ci" | "cyan_italic" => Some(Color::Cyan.italic().prefix().to_string()),
+        "cd" | "cyan_dimmed" => Some(Color::Cyan.dimmed().prefix().to_string()),
+        "cr" | "cyan_reverse" => Some(Color::Cyan.reverse().prefix().to_string()),
+        "w" | "white" => Some(Color::White.prefix().to_string()),
+        "wb" | "white_bold" => Some(Color::White.bold().prefix().to_string()),
+        "wu" | "white_underline" => Some(Color::White.underline().prefix().to_string()),
+        "wi" | "white_italic" => Some(Color::White.italic().prefix().to_string()),
+        "wd" | "white_dimmed" => Some(Color::White.dimmed().prefix().to_string()),
+        "wr" | "white_reverse" => Some(Color::White.reverse().prefix().to_string()),
+        "reset" => Some("\x1b[0m".to_owned()),
+        _ => None,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Ansi;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Ansi {})?)
+    }
+}

crates/nu-cli/src/commands/append.rs

@@ -1,17 +1,18 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
-use nu_protocol::{Signature, SyntaxShape, Value};
+use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
 
 #[derive(Deserialize)]
-struct AppendArgs {
-    row: Value,
+struct Arguments {
+    value: Value,
 }
 
-pub struct Append;
+pub struct Command;
 
-impl WholeStreamCommand for Append {
+#[async_trait]
+impl WholeStreamCommand for Command {
     fn name(&self) -> &str {
         "append"
     }
@@ -25,25 +26,65 @@ impl WholeStreamCommand for Append {
     }
 
     fn usage(&self) -> &str {
-        "Append the given row to the table"
+        "Append a row to the table"
     }
 
-    fn run(
+    async fn run(
         &self,
         args: CommandArgs,
         registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
-        args.process(registry, append)?.run()
+        let (Arguments { mut value }, input) = args.process(registry).await?;
+
+        let input: Vec<Value> = input.collect().await;
+
+        if let Some(first) = input.get(0) {
+            value.tag = first.tag();
+        }
+
+        // Checks if we are trying to append a row literal
+        if let Value {
+            value: UntaggedValue::Table(values),
+            tag,
+        } = &value
+        {
+            if values.len() == 1 && values[0].is_row() {
+                value = values[0].value.clone().into_value(tag);
+            }
+        }
+
+        Ok(futures::stream::iter(
+            input
+                .into_iter()
+                .chain(vec![value])
+                .map(ReturnSuccess::value),
+        )
+        .to_output_stream())
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        use nu_protocol::row;
+
+        vec![
+            Example {
+                description: "Add values to the end of the table",
+                example: "echo [1 2 3] | append 4",
+                result: Some(vec![
+                    UntaggedValue::int(1).into(),
+                    UntaggedValue::int(2).into(),
+                    UntaggedValue::int(3).into(),
+                    UntaggedValue::int(4).into(),
+                ]),
+            },
+            Example {
+                description: "Add row value to the end of the table",
+                example: "echo [[country]; [Ecuador] ['New Zealand']] | append [[country]; [USA]]",
+                result: Some(vec![
+                    row! { "country".into() => Value::from("Ecuador")},
+                    row! { "country".into() => Value::from("New Zealand")},
+                    row! { "country".into() => Value::from("USA")},
+                ]),
+            },
+        ]
     }
 }
-
-fn append(
-    AppendArgs { row }: AppendArgs,
-    RunnableContext { input, .. }: RunnableContext,
-) -> Result<OutputStream, ShellError> {
-    let mut after: VecDeque<Value> = VecDeque::new();
-    after.push_back(row);
-    let after = futures::stream::iter(after);
-
-    Ok(OutputStream::from_input(input.chain(after)))
-}

crates/nu-cli/src/commands/autoenv.rs

@@ -0,0 +1,92 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{ReturnSuccess, Signature, UntaggedValue};
+use serde::Deserialize;
+use serde::Serialize;
+use sha2::{Digest, Sha256};
+use std::io::Read;
+use std::path::PathBuf;
+pub struct Autoenv;
+
+#[derive(Deserialize, Serialize, Debug, Default)]
+pub struct Trusted {
+    pub files: IndexMap<String, Vec<u8>>,
+}
+impl Trusted {
+    pub fn new() -> Self {
+        Trusted {
+            files: IndexMap::new(),
+        }
+    }
+}
+pub fn file_is_trusted(nu_env_file: &PathBuf, content: &[u8]) -> Result<bool, ShellError> {
+    let contentdigest = Sha256::digest(&content).as_slice().to_vec();
+    let nufile = std::fs::canonicalize(nu_env_file)?;
+
+    let trusted = read_trusted()?;
+    Ok(trusted.files.get(&nufile.to_string_lossy().to_string()) == Some(&contentdigest))
+}
+
+pub fn read_trusted() -> Result<Trusted, ShellError> {
+    let config_path = config::default_path_for(&Some(PathBuf::from("nu-env.toml")))?;
+
+    let mut file = std::fs::OpenOptions::new()
+        .read(true)
+        .create(true)
+        .write(true)
+        .open(config_path)
+        .map_err(|_| ShellError::untagged_runtime_error("Couldn't open nu-env.toml"))?;
+    let mut doc = String::new();
+    file.read_to_string(&mut doc)?;
+
+    let allowed = toml::de::from_str(doc.as_str()).unwrap_or_else(|_| Trusted::new());
+    Ok(allowed)
+}
+
+#[async_trait]
+impl WholeStreamCommand for Autoenv {
+    fn name(&self) -> &str {
+        "autoenv"
+    }
+    fn usage(&self) -> &str {
+        // "Mark a .nu-env file in a directory as trusted. Needs to be re-run after each change to the file or its filepath."
+        r#"Manage directory specific environment variables and scripts. Create a file called .nu-env in any directory and run 'autoenv trust' to let nushell read it when entering the directory.
+The file can contain several optional sections:
+    env: environment variables to set when visiting the directory. The variables are unset after leaving the directory and any overwritten values are restored.
+    scriptvars: environment variables that should be set to the return value of a script. After they have been set, they behave in the same way as variables set in the env section.
+    scripts: scripts to run when entering the directory or leaving it."#
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("autoenv")
+    }
+    async fn run(
+        &self,
+        _args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        let registry = registry.clone();
+        Ok(OutputStream::one(ReturnSuccess::value(
+            UntaggedValue::string(crate::commands::help::get_help(&Autoenv, &registry))
+                .into_value(Tag::unknown()),
+        )))
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Example .nu-env file",
+            example: r#"cat .nu-env
+    [env]
+    mykey = "myvalue"
+
+    [scriptvars]
+    myscript = "echo myval"
+
+    [scripts]
+    entryscripts = ["touch hello.txt", "touch hello2.txt"]
+    exitscripts = ["touch bye.txt"]"#,
+            result: None,
+        }]
+    }
+}

crates/nu-cli/src/commands/autoenv_trust.rs

@@ -0,0 +1,83 @@
+use super::autoenv::read_trusted;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::SyntaxShape;
+use nu_protocol::{Primitive, ReturnSuccess, Signature, UntaggedValue, Value};
+use sha2::{Digest, Sha256};
+use std::{fs, path::PathBuf};
+pub struct AutoenvTrust;
+
+#[async_trait]
+impl WholeStreamCommand for AutoenvTrust {
+    fn name(&self) -> &str {
+        "autoenv trust"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("autoenv trust").optional("dir", SyntaxShape::String, "Directory to allow")
+    }
+
+    fn usage(&self) -> &str {
+        "Trust a .nu-env file in the current or given directory"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        let tag = args.call_info.name_tag.clone();
+
+        let file_to_trust = match args.call_info.evaluate(registry).await?.args.nth(0) {
+            Some(Value {
+                value: UntaggedValue::Primitive(Primitive::String(ref path)),
+                tag: _,
+            }) => {
+                let mut dir = fs::canonicalize(path)?;
+                dir.push(".nu-env");
+                dir
+            }
+            _ => {
+                let mut dir = fs::canonicalize(std::env::current_dir()?)?;
+                dir.push(".nu-env");
+                dir
+            }
+        };
+
+        let content = std::fs::read(&file_to_trust)?;
+
+        let filename = file_to_trust.to_string_lossy().to_string();
+        let mut allowed = read_trusted()?;
+        allowed
+            .files
+            .insert(filename, Sha256::digest(&content).as_slice().to_vec());
+
+        let config_path = config::default_path_for(&Some(PathBuf::from("nu-env.toml")))?;
+        let tomlstr = toml::to_string(&allowed).map_err(|_| {
+            ShellError::untagged_runtime_error("Couldn't serialize allowed dirs to nu-env.toml")
+        })?;
+        fs::write(config_path, tomlstr).expect("Couldn't write to toml file");
+
+        Ok(OutputStream::one(ReturnSuccess::value(
+            UntaggedValue::string(".nu-env trusted!").into_value(tag),
+        )))
+    }
+    fn is_binary(&self) -> bool {
+        false
+    }
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Allow .nu-env file in current directory",
+                example: "autoenv trust",
+                result: None,
+            },
+            Example {
+                description: "Allow .nu-env file in directory foo",
+                example: "autoenv trust foo",
+                result: None,
+            },
+        ]
+    }
+}

crates/nu-cli/src/commands/autoenv_untrust.rs

@@ -0,0 +1,107 @@
+use super::autoenv::Trusted;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::SyntaxShape;
+use nu_protocol::{Primitive, ReturnSuccess, Signature, UntaggedValue, Value};
+use std::io::Read;
+use std::{fs, path::PathBuf};
+pub struct AutoenvUnTrust;
+
+#[async_trait]
+impl WholeStreamCommand for AutoenvUnTrust {
+    fn name(&self) -> &str {
+        "autoenv untrust"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("autoenv untrust").optional(
+            "dir",
+            SyntaxShape::String,
+            "Directory to disallow",
+        )
+    }
+
+    fn usage(&self) -> &str {
+        "Untrust a .nu-env file in the current or given directory"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        let tag = args.call_info.name_tag.clone();
+        let file_to_untrust = match args.call_info.evaluate(registry).await?.args.nth(0) {
+            Some(Value {
+                value: UntaggedValue::Primitive(Primitive::String(ref path)),
+                tag: _,
+            }) => {
+                let mut dir = fs::canonicalize(path)?;
+                dir.push(".nu-env");
+                dir
+            }
+            _ => {
+                let mut dir = std::env::current_dir()?;
+                dir.push(".nu-env");
+                dir
+            }
+        };
+
+        let config_path = config::default_path_for(&Some(PathBuf::from("nu-env.toml")))?;
+
+        let mut file = match std::fs::OpenOptions::new()
+            .read(true)
+            .create(true)
+            .write(true)
+            .open(config_path.clone())
+        {
+            Ok(p) => p,
+            Err(_) => {
+                return Err(ShellError::untagged_runtime_error(
+                    "Couldn't open nu-env.toml",
+                ));
+            }
+        };
+
+        let mut doc = String::new();
+        file.read_to_string(&mut doc)?;
+
+        let mut allowed: Trusted = toml::from_str(doc.as_str()).unwrap_or_else(|_| Trusted::new());
+
+        let file_to_untrust = file_to_untrust.to_string_lossy().to_string();
+
+        if allowed.files.remove(&file_to_untrust).is_none() {
+            return
+                Err(ShellError::untagged_runtime_error(
+                    "No .nu-env file to untrust in the given directory. Is it missing, or already untrusted?",
+                ));
+        }
+
+        let tomlstr = toml::to_string(&allowed).map_err(|_| {
+            ShellError::untagged_runtime_error("Couldn't serialize allowed dirs to nu-env.toml")
+        })?;
+        fs::write(config_path, tomlstr).expect("Couldn't write to toml file");
+
+        Ok(OutputStream::one(ReturnSuccess::value(
+            UntaggedValue::string(".nu-env untrusted!").into_value(tag),
+        )))
+    }
+    fn is_binary(&self) -> bool {
+        false
+    }
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Disallow .nu-env file in current directory",
+                example: "autoenv untrust",
+                result: None,
+            },
+            Example {
+                description: "Disallow .nu-env file in directory foo",
+                example: "autoenv untrust foo",
+                result: None,
+            },
+        ]
+    }
+}

crates/nu-cli/src/commands/autoview.rs

@@ -1,300 +0,0 @@
-use crate::commands::UnevaluatedCallInfo;
-use crate::commands::WholeStreamCommand;
-use crate::prelude::*;
-use nu_errors::ShellError;
-use nu_protocol::{hir, hir::Expression, hir::Literal, hir::SpannedExpression};
-use nu_protocol::{Primitive, ReturnSuccess, Scope, Signature, UntaggedValue, Value};
-use std::sync::atomic::AtomicBool;
-use std::sync::atomic::Ordering;
-
-pub struct Autoview;
-
-impl WholeStreamCommand for Autoview {
-    fn name(&self) -> &str {
-        "autoview"
-    }
-
-    fn signature(&self) -> Signature {
-        Signature::build("autoview")
-    }
-
-    fn usage(&self) -> &str {
-        "View the contents of the pipeline as a table or list."
-    }
-
-    fn run(
-        &self,
-        args: CommandArgs,
-        registry: &CommandRegistry,
-    ) -> Result<OutputStream, ShellError> {
-        autoview(RunnableContext {
-            input: args.input,
-            registry: registry.clone(),
-            shell_manager: args.shell_manager,
-            host: args.host,
-            ctrl_c: args.ctrl_c,
-            name: args.call_info.name_tag,
-        })
-    }
-}
-
-pub struct RunnableContextWithoutInput {
-    pub shell_manager: ShellManager,
-    pub host: Arc<parking_lot::Mutex<Box<dyn Host>>>,
-    pub ctrl_c: Arc<AtomicBool>,
-    pub registry: CommandRegistry,
-    pub name: Tag,
-}
-
-impl RunnableContextWithoutInput {
-    pub fn convert(context: RunnableContext) -> (InputStream, RunnableContextWithoutInput) {
-        let new_context = RunnableContextWithoutInput {
-            shell_manager: context.shell_manager,
-            host: context.host,
-            ctrl_c: context.ctrl_c,
-            registry: context.registry,
-            name: context.name,
-        };
-        (context.input, new_context)
-    }
-}
-
-pub fn autoview(context: RunnableContext) -> Result<OutputStream, ShellError> {
-    let binary = context.get_command("binaryview");
-    let text = context.get_command("textview");
-    let table = context.get_command("table");
-
-    Ok(OutputStream::new(async_stream! {
-        let (mut input_stream, context) = RunnableContextWithoutInput::convert(context);
-
-        match input_stream.next().await {
-            Some(x) => {
-                match input_stream.next().await {
-                    Some(y) => {
-                        let ctrl_c = context.ctrl_c.clone();
-                        let stream = async_stream! {
-                            yield Ok(x);
-                            yield Ok(y);
-
-                            loop {
-                                match input_stream.next().await {
-                                    Some(z) => {
-                                        if ctrl_c.load(Ordering::SeqCst) {
-                                            break;
-                                        }
-                                        yield Ok(z);
-                                    }
-                                    _ => break,
-                                }
-                            }
-                        };
-                        let stream = stream.to_input_stream();
-
-                        if let Some(table) = table {
-                            let command_args = create_default_command_args(&context).with_input(stream);
-                            let result = table.run(command_args, &context.registry);
-                            result.collect::<Vec<_>>().await;
-                        }
-                    }
-                    _ => {
-                        match x {
-                            Value {
-                                value: UntaggedValue::Primitive(Primitive::String(ref s)),
-                                tag: Tag { anchor, span },
-                            } if anchor.is_some() => {
-                                if let Some(text) = text {
-                                    let mut stream = VecDeque::new();
-                                    stream.push_back(UntaggedValue::string(s).into_value(Tag { anchor, span }));
-                                    let command_args = create_default_command_args(&context).with_input(stream);
-                                    let result = text.run(command_args, &context.registry);
-                                    result.collect::<Vec<_>>().await;
-                                } else {
-                                    out!("{}", s);
-                                }
-                            }
-                            Value {
-                                value: UntaggedValue::Primitive(Primitive::String(s)),
-                                ..
-                            } => {
-                                out!("{}", s);
-                            }
-                            Value {
-                                value: UntaggedValue::Primitive(Primitive::Line(ref s)),
-                                tag: Tag { anchor, span },
-                            } if anchor.is_some() => {
-                                if let Some(text) = text {
-                                    let mut stream = VecDeque::new();
-                                    stream.push_back(UntaggedValue::string(s).into_value(Tag { anchor, span }));
-                                    let command_args = create_default_command_args(&context).with_input(stream);
-                                    let result = text.run(command_args, &context.registry);
-                                    result.collect::<Vec<_>>().await;
-                                } else {
-                                    out!("{}\n", s);
-                                }
-                            }
-                            Value {
-                                value: UntaggedValue::Primitive(Primitive::Line(s)),
-                                ..
-                            } => {
-                                out!("{}\n", s);
-                            }
-                            Value {
-                                value: UntaggedValue::Primitive(Primitive::Path(s)),
-                                ..
-                            } => {
-                                out!("{}", s.display());
-                            }
-                            Value {
-                                value: UntaggedValue::Primitive(Primitive::Int(n)),
-                                ..
-                            } => {
-                                out!("{}", n);
-                            }
-                            Value {
-                                value: UntaggedValue::Primitive(Primitive::Decimal(n)),
-                                ..
-                            } => {
-                                out!("{}", n);
-                            }
-                            Value {
-                                value: UntaggedValue::Primitive(Primitive::Boolean(b)),
-                                ..
-                            } => {
-                                out!("{}", b);
-                            }
-
-                            Value { value: UntaggedValue::Primitive(Primitive::Binary(ref b)), .. } => {
-                                if let Some(binary) = binary {
-                                    let mut stream = VecDeque::new();
-                                    stream.push_back(x);
-                                    let command_args = create_default_command_args(&context).with_input(stream);
-                                    let result = binary.run(command_args, &context.registry);
-                                    result.collect::<Vec<_>>().await;
-                                } else {
-                                    use pretty_hex::*;
-                                    out!("{:?}", b.hex_dump());
-                                }
-                            }
-
-                            Value { value: UntaggedValue::Error(e), .. } => {
-                                yield Err(e);
-                            }
-
-                            Value { value: UntaggedValue::Row(row), ..} => {
-                                use prettytable::format::{FormatBuilder, LinePosition, LineSeparator};
-                                use prettytable::{color, Attr, Cell, Row, Table};
-                                use crate::data::value::{format_leaf, style_leaf};
-                                use textwrap::fill;
-
-                                let termwidth = std::cmp::max(textwrap::termwidth(), 20);
-
-                                enum TableMode {
-                                    Light,
-                                    Normal,
-                                }
-
-                                let mut table = Table::new();
-                                let table_mode = crate::data::config::config(Tag::unknown());
-
-                                let table_mode = if let Some(s) = table_mode?.get("table_mode") {
-                                    match s.as_string() {
-                                        Ok(typ) if typ == "light" => TableMode::Light,
-                                        _ => TableMode::Normal,
-                                    }
-                                } else {
-                                    TableMode::Normal
-                                };
-
-                                match table_mode {
-                                    TableMode::Light => {
-                                        table.set_format(
-                                            FormatBuilder::new()
-                                                .separator(LinePosition::Title, LineSeparator::new('─', '─', ' ', ' '))
-                                                .padding(1, 1)
-                                                .build(),
-                                        );
-                                    }
-                                    _ => {
-                                        table.set_format(
-                                            FormatBuilder::new()
-                                                .column_separator('│')
-                                                .separator(LinePosition::Top, LineSeparator::new('─', '┬', ' ', ' '))
-                                                .separator(LinePosition::Title, LineSeparator::new('─', '┼', ' ', ' '))
-                                                .separator(LinePosition::Bottom, LineSeparator::new('─', '┴', ' ', ' '))
-                                                .padding(1, 1)
-                                                .build(),
-                                        );
-                                    }
-                                }
-
-                                let mut max_key_len = 0;
-                                for (key, _) in row.entries.iter() {
-                                    max_key_len = std::cmp::max(max_key_len, key.chars().count());
-                                }
-
-                                if max_key_len > (termwidth/2 - 1) {
-                                    max_key_len = termwidth/2 - 1;
-                                }
-
-                                let max_val_len = termwidth - max_key_len - 5;
-
-                                for (key, value) in row.entries.iter() {
-                                    table.add_row(Row::new(vec![Cell::new(&fill(&key, max_key_len)).with_style(Attr::ForegroundColor(color::GREEN)).with_style(Attr::Bold),
-                                        Cell::new(&fill(&format_leaf(value).plain_string(100_000), max_val_len))]));
-                                }
-
-                                table.printstd();
-
-                                // table.print_term(&mut *context.host.lock().out_terminal().ok_or_else(|| ShellError::untagged_runtime_error("Could not open terminal for output"))?)
-                                //     .map_err(|_| ShellError::untagged_runtime_error("Internal error: could not print to terminal (for unix systems check to make sure TERM is set)"))?;
-                            }
-
-                            Value { value: ref item, .. } => {
-                                if let Some(table) = table {
-                                    let mut stream = VecDeque::new();
-                                    stream.push_back(x);
-                                    let command_args = create_default_command_args(&context).with_input(stream);
-                                    let result = table.run(command_args, &context.registry);
-                                    result.collect::<Vec<_>>().await;
-                                } else {
-                                    out!("{:?}", item);
-                                }
-                            }
-                        }
-                    }
-                }
-            }
-            _ => {
-                //out!("<no results>");
-            }
-        }
-
-        // Needed for async_stream to type check
-        if false {
-            yield ReturnSuccess::value(UntaggedValue::nothing().into_untagged_value());
-        }
-    }))
-}
-
-fn create_default_command_args(context: &RunnableContextWithoutInput) -> RawCommandArgs {
-    let span = context.name.span;
-    RawCommandArgs {
-        host: context.host.clone(),
-        ctrl_c: context.ctrl_c.clone(),
-        shell_manager: context.shell_manager.clone(),
-        call_info: UnevaluatedCallInfo {
-            args: hir::Call {
-                head: Box::new(SpannedExpression::new(
-                    Expression::Literal(Literal::String(String::new())),
-                    span,
-                )),
-                positional: None,
-                named: None,
-                span,
-                is_last: true,
-            },
-            name_tag: context.name.clone(),
-            scope: Scope::empty(),
-        },
-    }
-}

crates/nu-cli/src/commands/autoview/command.rs

@@ -0,0 +1,337 @@
+use crate::commands::autoview::options::{ConfigExtensions, NuConfig as AutoViewConfiguration};
+use crate::commands::{UnevaluatedCallInfo, WholeStreamCommand};
+use crate::prelude::*;
+use crate::primitive::get_color_config;
+use nu_data::value::format_leaf;
+use nu_errors::ShellError;
+use nu_protocol::hir::{self, Expression, ExternalRedirection, Literal, SpannedExpression};
+use nu_protocol::{Primitive, Scope, Signature, UntaggedValue, Value};
+use nu_table::TextStyle;
+use parking_lot::Mutex;
+use std::sync::atomic::AtomicBool;
+
+pub struct Command;
+
+#[async_trait]
+impl WholeStreamCommand for Command {
+    fn name(&self) -> &str {
+        "autoview"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("autoview")
+    }
+
+    fn usage(&self) -> &str {
+        "View the contents of the pipeline as a table or list."
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        autoview(RunnableContext {
+            input: args.input,
+            registry: registry.clone(),
+            shell_manager: args.shell_manager,
+            host: args.host,
+            ctrl_c: args.ctrl_c,
+            current_errors: args.current_errors,
+            name: args.call_info.name_tag,
+            raw_input: args.raw_input,
+        })
+        .await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Automatically view the results",
+                example: "ls | autoview",
+                result: None,
+            },
+            Example {
+                description: "Autoview is also implied. The above can be written as",
+                example: "ls",
+                result: None,
+            },
+        ]
+    }
+}
+
+pub struct RunnableContextWithoutInput {
+    pub shell_manager: ShellManager,
+    pub host: Arc<parking_lot::Mutex<Box<dyn Host>>>,
+    pub current_errors: Arc<Mutex<Vec<ShellError>>>,
+    pub ctrl_c: Arc<AtomicBool>,
+    pub registry: CommandRegistry,
+    pub name: Tag,
+}
+
+impl RunnableContextWithoutInput {
+    pub fn convert(context: RunnableContext) -> (InputStream, RunnableContextWithoutInput) {
+        let new_context = RunnableContextWithoutInput {
+            shell_manager: context.shell_manager,
+            host: context.host,
+            ctrl_c: context.ctrl_c,
+            current_errors: context.current_errors,
+            registry: context.registry,
+            name: context.name,
+        };
+        (context.input, new_context)
+    }
+}
+
+pub async fn autoview(context: RunnableContext) -> Result<OutputStream, ShellError> {
+    let configuration = AutoViewConfiguration::new();
+
+    let binary = context.get_command("binaryview");
+    let text = context.get_command("textview");
+    let table = context.get_command("table");
+
+    let pivot_mode = configuration.pivot_mode();
+
+    let (mut input_stream, context) = RunnableContextWithoutInput::convert(context);
+    let term_width = context.host.lock().width();
+    let color_hm = get_color_config();
+
+    if let Some(x) = input_stream.next().await {
+        match input_stream.next().await {
+            Some(y) => {
+                let ctrl_c = context.ctrl_c.clone();
+                let xy = vec![x, y];
+                let xy_stream = futures::stream::iter(xy)
+                    .chain(input_stream)
+                    .interruptible(ctrl_c);
+
+                let stream = InputStream::from_stream(xy_stream);
+
+                if let Some(table) = table {
+                    let command_args = create_default_command_args(&context).with_input(stream);
+                    let result = table.run(command_args, &context.registry).await?;
+                    result.collect::<Vec<_>>().await;
+                }
+            }
+            _ => {
+                match x {
+                    Value {
+                        value: UntaggedValue::Primitive(Primitive::String(ref s)),
+                        tag: Tag { anchor, span },
+                    } if anchor.is_some() => {
+                        if let Some(text) = text {
+                            let mut stream = VecDeque::new();
+                            stream.push_back(
+                                UntaggedValue::string(s).into_value(Tag { anchor, span }),
+                            );
+                            let command_args =
+                                create_default_command_args(&context).with_input(stream);
+                            let result = text.run(command_args, &context.registry).await?;
+                            result.collect::<Vec<_>>().await;
+                        } else {
+                            out!("{}", s);
+                        }
+                    }
+                    Value {
+                        value: UntaggedValue::Primitive(Primitive::String(s)),
+                        ..
+                    } => {
+                        out!("{}", s);
+                    }
+                    Value {
+                        value: UntaggedValue::Primitive(Primitive::Line(ref s)),
+                        tag: Tag { anchor, span },
+                    } if anchor.is_some() => {
+                        if let Some(text) = text {
+                            let mut stream = VecDeque::new();
+                            stream.push_back(
+                                UntaggedValue::string(s).into_value(Tag { anchor, span }),
+                            );
+                            let command_args =
+                                create_default_command_args(&context).with_input(stream);
+                            let result = text.run(command_args, &context.registry).await?;
+                            result.collect::<Vec<_>>().await;
+                        } else {
+                            out!("{}\n", s);
+                        }
+                    }
+                    Value {
+                        value: UntaggedValue::Primitive(Primitive::Line(s)),
+                        ..
+                    } => {
+                        out!("{}\n", s);
+                    }
+                    Value {
+                        value: UntaggedValue::Primitive(Primitive::Path(s)),
+                        ..
+                    } => {
+                        out!("{}", s.display());
+                    }
+                    Value {
+                        value: UntaggedValue::Primitive(Primitive::Int(n)),
+                        ..
+                    } => {
+                        out!("{}", n);
+                    }
+                    Value {
+                        value: UntaggedValue::Primitive(Primitive::Decimal(n)),
+                        ..
+                    } => {
+                        // TODO: normalize decimal to remove trailing zeros.
+                        // normalization will be available in next release of bigdecimal crate
+                        let mut output = n.to_string();
+                        if output.contains('.') {
+                            output = output.trim_end_matches('0').to_owned();
+                        }
+                        if output.ends_with('.') {
+                            output.push('0');
+                        }
+                        out!("{}", output);
+                    }
+                    Value {
+                        value: UntaggedValue::Primitive(Primitive::Boolean(b)),
+                        ..
+                    } => {
+                        out!("{}", b);
+                    }
+                    Value {
+                        value: UntaggedValue::Primitive(Primitive::Duration(_)),
+                        ..
+                    } => {
+                        let output = format_leaf(&x).plain_string(100_000);
+                        out!("{}", output);
+                    }
+                    Value {
+                        value: UntaggedValue::Primitive(Primitive::Date(d)),
+                        ..
+                    } => {
+                        out!("{}", d);
+                    }
+                    Value {
+                        value: UntaggedValue::Primitive(Primitive::Range(_)),
+                        ..
+                    } => {
+                        let output = format_leaf(&x).plain_string(100_000);
+                        out!("{}", output);
+                    }
+
+                    Value {
+                        value: UntaggedValue::Primitive(Primitive::Binary(ref b)),
+                        ..
+                    } => {
+                        if let Some(binary) = binary {
+                            let mut stream = VecDeque::new();
+                            stream.push_back(x);
+                            let command_args =
+                                create_default_command_args(&context).with_input(stream);
+                            let result = binary.run(command_args, &context.registry).await?;
+                            result.collect::<Vec<_>>().await;
+                        } else {
+                            use pretty_hex::*;
+                            out!("{:?}", b.hex_dump());
+                        }
+                    }
+
+                    Value {
+                        value: UntaggedValue::Error(e),
+                        ..
+                    } => {
+                        return Err(e);
+                    }
+
+                    Value {
+                        value: UntaggedValue::Row(row),
+                        ..
+                    } if pivot_mode.is_always()
+                        || (pivot_mode.is_auto()
+                            && (row
+                                .entries
+                                .iter()
+                                .map(|(_, v)| v.convert_to_string())
+                                .collect::<Vec<_>>()
+                                .iter()
+                                .fold(0usize, |acc, len| acc + len.len())
+                                + row.entries.iter().count() * 2)
+                                > term_width) =>
+                    {
+                        let mut entries = vec![];
+                        for (key, value) in row.entries.iter() {
+                            entries.push(vec![
+                                nu_table::StyledString::new(
+                                    key.to_string(),
+                                    TextStyle::new()
+                                        .alignment(nu_table::Alignment::Left)
+                                        .fg(ansi_term::Color::Green)
+                                        .bold(Some(true)),
+                                ),
+                                nu_table::StyledString::new(
+                                    format_leaf(value).plain_string(100_000),
+                                    nu_table::TextStyle::basic_left(),
+                                ),
+                            ]);
+                        }
+
+                        let table =
+                            nu_table::Table::new(vec![], entries, nu_table::Theme::compact());
+
+                        nu_table::draw_table(&table, term_width, &color_hm);
+                    }
+
+                    Value {
+                        value: ref item, ..
+                    } => {
+                        if let Some(table) = table {
+                            let mut stream = VecDeque::new();
+                            stream.push_back(x);
+                            let command_args =
+                                create_default_command_args(&context).with_input(stream);
+                            let result = table.run(command_args, &context.registry).await?;
+                            result.collect::<Vec<_>>().await;
+                        } else {
+                            out!("{:?}", item);
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    Ok(OutputStream::empty())
+}
+
+fn create_default_command_args(context: &RunnableContextWithoutInput) -> RawCommandArgs {
+    let span = context.name.span;
+    RawCommandArgs {
+        host: context.host.clone(),
+        ctrl_c: context.ctrl_c.clone(),
+        current_errors: context.current_errors.clone(),
+        shell_manager: context.shell_manager.clone(),
+        call_info: UnevaluatedCallInfo {
+            args: hir::Call {
+                head: Box::new(SpannedExpression::new(
+                    Expression::Literal(Literal::String(String::new())),
+                    span,
+                )),
+                positional: None,
+                named: None,
+                span,
+                external_redirection: ExternalRedirection::Stdout,
+            },
+            name_tag: context.name.clone(),
+            scope: Scope::create(),
+        },
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Command;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Command {})?)
+    }
+}

crates/nu-cli/src/commands/autoview/mod.rs

@@ -0,0 +1,4 @@
+pub mod command;
+mod options;
+
+pub use command::Command as Autoview;

crates/nu-cli/src/commands/autoview/options.rs

@@ -0,0 +1,51 @@
+pub use nu_data::config::NuConfig;
+use std::fmt::Debug;
+
+#[derive(PartialEq, Debug)]
+pub enum AutoPivotMode {
+    Auto,
+    Always,
+    Never,
+}
+
+impl AutoPivotMode {
+    pub fn is_auto(&self) -> bool {
+        matches!(self, AutoPivotMode::Auto)
+    }
+
+    pub fn is_always(&self) -> bool {
+        matches!(self, AutoPivotMode::Always)
+    }
+
+    #[allow(unused)]
+    pub fn is_never(&self) -> bool {
+        matches!(self, AutoPivotMode::Never)
+    }
+}
+
+pub trait ConfigExtensions: Debug + Send {
+    fn pivot_mode(&self) -> AutoPivotMode;
+}
+
+pub fn pivot_mode(config: &NuConfig) -> AutoPivotMode {
+    let vars = &config.vars;
+
+    if let Some(mode) = vars.get("pivot_mode") {
+        let mode = match mode.as_string() {
+            Ok(m) if m.to_lowercase() == "auto" => AutoPivotMode::Auto,
+            Ok(m) if m.to_lowercase() == "always" => AutoPivotMode::Always,
+            Ok(m) if m.to_lowercase() == "never" => AutoPivotMode::Never,
+            _ => AutoPivotMode::Never,
+        };
+
+        return mode;
+    }
+
+    AutoPivotMode::Never
+}
+
+impl ConfigExtensions for NuConfig {
+    fn pivot_mode(&self) -> AutoPivotMode {
+        pivot_mode(self)
+    }
+}

crates/nu-cli/src/commands/benchmark.rs

@@ -0,0 +1,212 @@
+use crate::commands::classified::block::run_block;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+#[cfg(feature = "rich-benchmark")]
+use heim::cpu::time;
+use nu_errors::ShellError;
+use nu_protocol::{
+    hir::{Block, ClassifiedCommand, Commands, InternalCommand},
+    Dictionary, Scope, Signature, SyntaxShape, UntaggedValue, Value,
+};
+use rand::{
+    distributions::Alphanumeric,
+    prelude::{thread_rng, Rng},
+};
+use std::convert::TryInto;
+use std::time::{Duration, Instant};
+
+pub struct Benchmark;
+
+#[derive(Deserialize, Debug)]
+struct BenchmarkArgs {
+    block: Block,
+    passthrough: Option<Block>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for Benchmark {
+    fn name(&self) -> &str {
+        "benchmark"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("benchmark")
+            .required(
+                "block",
+                SyntaxShape::Block,
+                "the block to run and benchmark",
+            )
+            .named(
+                "passthrough",
+                SyntaxShape::Block,
+                "Display the benchmark results and pass through the block's output",
+                Some('p'),
+            )
+    }
+
+    fn usage(&self) -> &str {
+        "Runs a block and returns the time it took to execute it"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        benchmark(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Benchmarks a command within a block",
+                example: "benchmark { sleep 500ms }",
+                result: None,
+            },
+            Example {
+                description: "Benchmarks a command within a block and passes its output through",
+                example: "echo 45 | benchmark { sleep 500ms } --passthrough {}",
+                result: Some(vec![UntaggedValue::int(45).into()]),
+            },
+        ]
+    }
+}
+
+async fn benchmark(
+    raw_args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+
+    let tag = raw_args.call_info.args.span;
+    let mut context = EvaluationContext::from_raw(&raw_args, &registry);
+    let scope = raw_args.call_info.scope.clone();
+    let (BenchmarkArgs { block, passthrough }, input) = raw_args.process(&registry).await?;
+
+    let env = scope.env();
+    let name = generate_free_name(&env);
+    let mut env = IndexMap::new();
+    env.insert(name, generate_random_env_value());
+    let scope = Scope::append_env(scope, env);
+
+    let start_time = Instant::now();
+
+    #[cfg(feature = "rich-benchmark")]
+    let start = time().await;
+
+    let result = run_block(&block, &mut context, input, scope.clone()).await;
+    let output = result?.into_vec().await;
+
+    #[cfg(feature = "rich-benchmark")]
+    let end = time().await;
+
+    let end_time = Instant::now();
+    context.clear_errors();
+
+    // return basic runtime
+    #[cfg(not(feature = "rich-benchmark"))]
+    {
+        let mut indexmap = IndexMap::with_capacity(1);
+
+        let real_time = into_big_int(end_time - start_time);
+        indexmap.insert("real time".to_string(), real_time);
+        benchmark_output(indexmap, output, passthrough, &tag, &mut context, scope).await
+    }
+    // return advanced stats
+    #[cfg(feature = "rich-benchmark")]
+    if let (Ok(start), Ok(end)) = (start, end) {
+        let mut indexmap = IndexMap::with_capacity(4);
+
+        let real_time = into_big_int(end_time - start_time);
+        indexmap.insert("real time".to_string(), real_time);
+
+        let user_time = into_big_int(end.user() - start.user());
+        indexmap.insert("user time".to_string(), user_time);
+
+        let system_time = into_big_int(end.system() - start.system());
+        indexmap.insert("system time".to_string(), system_time);
+
+        let idle_time = into_big_int(end.idle() - start.idle());
+        indexmap.insert("idle time".to_string(), idle_time);
+
+        benchmark_output(indexmap, output, passthrough, &tag, &mut context, scope).await
+    } else {
+        Err(ShellError::untagged_runtime_error(
+            "Could not retreive CPU time",
+        ))
+    }
+}
+
+async fn benchmark_output<T, Output>(
+    indexmap: IndexMap<String, BigInt>,
+    block_output: Output,
+    passthrough: Option<Block>,
+    tag: T,
+    context: &mut EvaluationContext,
+    scope: Arc<Scope>,
+) -> Result<OutputStream, ShellError>
+where
+    T: Into<Tag> + Copy,
+    Output: Into<OutputStream>,
+{
+    let value = UntaggedValue::Row(Dictionary::from(
+        indexmap
+            .into_iter()
+            .map(|(k, v)| (k, UntaggedValue::duration(v).into_value(tag)))
+            .collect::<IndexMap<String, Value>>(),
+    ))
+    .into_value(tag);
+
+    if let Some(time_block) = passthrough {
+        let benchmark_output = InputStream::one(value);
+
+        // add autoview for an empty block
+        let time_block = add_implicit_autoview(time_block);
+
+        let _ = run_block(&time_block, context, benchmark_output, scope).await?;
+        context.clear_errors();
+
+        Ok(block_output.into())
+    } else {
+        let benchmark_output = OutputStream::one(value);
+        Ok(benchmark_output)
+    }
+}
+
+fn add_implicit_autoview(mut block: Block) -> Block {
+    if block.block.is_empty() {
+        block.push({
+            let mut commands = Commands::new(block.span);
+            commands.push(ClassifiedCommand::Internal(InternalCommand::new(
+                "autoview".to_string(),
+                block.span,
+                block.span,
+            )));
+            commands
+        });
+    }
+    block
+}
+
+fn into_big_int<T: TryInto<Duration>>(time: T) -> BigInt {
+    time.try_into()
+        .unwrap_or_else(|_| Duration::new(0, 0))
+        .as_nanos()
+        .into()
+}
+
+fn generate_random_env_value() -> String {
+    let mut thread_rng = thread_rng();
+    let len = thread_rng.gen_range(1, 16 * 1024);
+    thread_rng.sample_iter(&Alphanumeric).take(len).collect()
+}
+
+fn generate_free_name(env: &indexmap::IndexMap<String, String>) -> String {
+    let mut thread_rng = thread_rng();
+    loop {
+        let candidate_name = format!("NU_RANDOM_VALUE_{}", thread_rng.gen::<usize>());
+        if !env.contains_key(&candidate_name) {
+            return candidate_name;
+        }
+    }
+}

crates/nu-cli/src/commands/build_string.rs

@@ -0,0 +1,56 @@
+use crate::prelude::*;
+use nu_errors::ShellError;
+
+use crate::commands::WholeStreamCommand;
+use nu_data::value::format_leaf;
+use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
+
+#[derive(Deserialize)]
+pub struct BuildStringArgs {
+    rest: Vec<Value>,
+}
+
+pub struct BuildString;
+
+#[async_trait]
+impl WholeStreamCommand for BuildString {
+    fn name(&self) -> &str {
+        "build-string"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("build-string")
+            .rest(SyntaxShape::Any, "all values to form into the string")
+    }
+
+    fn usage(&self) -> &str {
+        "Builds a string from the arguments"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        let tag = args.call_info.name_tag.clone();
+        let (BuildStringArgs { rest }, _) = args.process(&registry).await?;
+
+        let mut output_string = String::new();
+
+        for r in rest {
+            output_string.push_str(&format_leaf(&r).plain_string(100_000))
+        }
+
+        Ok(OutputStream::one(ReturnSuccess::value(
+            UntaggedValue::string(output_string).into_value(tag),
+        )))
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Builds a string from a string and a number, without spaces between them",
+            example: "build-string 'foo' 3",
+            result: None,
+        }]
+    }
+}

crates/nu-cli/src/commands/cal.rs

@@ -0,0 +1,350 @@
+use crate::commands::{command::EvaluatedWholeStreamCommandArgs, WholeStreamCommand};
+use crate::prelude::*;
+use chrono::{Datelike, Local, NaiveDate};
+use indexmap::IndexMap;
+use nu_errors::ShellError;
+use nu_protocol::{Dictionary, Signature, SyntaxShape, UntaggedValue, Value};
+
+pub struct Cal;
+
+#[async_trait]
+impl WholeStreamCommand for Cal {
+    fn name(&self) -> &str {
+        "cal"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("cal")
+            .switch("year", "Display the year column", Some('y'))
+            .switch("quarter", "Display the quarter column", Some('q'))
+            .switch("month", "Display the month column", Some('m'))
+            .named(
+                "full-year",
+                SyntaxShape::Int,
+                "Display a year-long calendar for the specified year",
+                None,
+            )
+            .named(
+                "week-start",
+                SyntaxShape::String,
+                "Display the calendar with the specified day as the first day of the week",
+                None,
+            )
+            .switch(
+                "month-names",
+                "Display the month names instead of integers",
+                None,
+            )
+    }
+
+    fn usage(&self) -> &str {
+        "Display a calendar."
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        cal(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "This month's calendar",
+                example: "cal",
+                result: None,
+            },
+            Example {
+                description: "The calendar for all of 2012",
+                example: "cal --full-year 2012",
+                result: None,
+            },
+            Example {
+                description: "This month's calendar with the week starting on monday",
+                example: "cal --week-start monday",
+                result: None,
+            },
+        ]
+    }
+}
+
+pub async fn cal(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+    let args = args.evaluate_once(&registry).await?;
+    let mut calendar_vec_deque = VecDeque::new();
+    let tag = args.call_info.name_tag.clone();
+
+    let (current_year, current_month, current_day) = get_current_date();
+
+    let mut selected_year: i32 = current_year;
+    let mut current_day_option: Option<u32> = Some(current_day);
+
+    let month_range = if let Some(full_year_value) = args.get("full-year") {
+        if let Ok(year_u64) = full_year_value.as_u64() {
+            selected_year = year_u64 as i32;
+
+            if selected_year != current_year {
+                current_day_option = None
+            }
+        } else {
+            return Err(get_invalid_year_shell_error(&full_year_value.tag()));
+        }
+
+        (1, 12)
+    } else {
+        (current_month, current_month)
+    };
+
+    add_months_of_year_to_table(
+        &args,
+        &mut calendar_vec_deque,
+        &tag,
+        selected_year,
+        month_range,
+        current_month,
+        current_day_option,
+    )?;
+
+    Ok(futures::stream::iter(calendar_vec_deque).to_output_stream())
+}
+
+fn get_invalid_year_shell_error(year_tag: &Tag) -> ShellError {
+    ShellError::labeled_error("The year is invalid", "invalid year", year_tag)
+}
+
+struct MonthHelper {
+    selected_year: i32,
+    selected_month: u32,
+    day_number_of_week_month_starts_on: u32,
+    number_of_days_in_month: u32,
+    quarter_number: u32,
+    month_name: String,
+}
+
+impl MonthHelper {
+    pub fn new(selected_year: i32, selected_month: u32) -> Result<MonthHelper, ()> {
+        let naive_date = NaiveDate::from_ymd_opt(selected_year, selected_month, 1).ok_or(())?;
+        let number_of_days_in_month =
+            MonthHelper::calculate_number_of_days_in_month(selected_year, selected_month)?;
+
+        Ok(MonthHelper {
+            selected_year,
+            selected_month,
+            day_number_of_week_month_starts_on: naive_date.weekday().num_days_from_sunday(),
+            number_of_days_in_month,
+            quarter_number: ((selected_month - 1) / 3) + 1,
+            month_name: naive_date.format("%B").to_string().to_ascii_lowercase(),
+        })
+    }
+
+    fn calculate_number_of_days_in_month(
+        mut selected_year: i32,
+        mut selected_month: u32,
+    ) -> Result<u32, ()> {
+        // Chrono does not provide a method to output the amount of days in a month
+        // This is a workaround taken from the example code from the Chrono docs here:
+        // https://docs.rs/chrono/0.3.0/chrono/naive/date/struct.NaiveDate.html#example-30
+        if selected_month == 12 {
+            selected_year += 1;
+            selected_month = 1;
+        } else {
+            selected_month += 1;
+        };
+
+        let next_month_naive_date =
+            NaiveDate::from_ymd_opt(selected_year, selected_month, 1).ok_or(())?;
+
+        Ok(next_month_naive_date.pred().day())
+    }
+}
+
+fn get_current_date() -> (i32, u32, u32) {
+    let local_now_date = Local::now().date();
+
+    let current_year: i32 = local_now_date.year();
+    let current_month: u32 = local_now_date.month();
+    let current_day: u32 = local_now_date.day();
+
+    (current_year, current_month, current_day)
+}
+
+fn add_months_of_year_to_table(
+    args: &EvaluatedWholeStreamCommandArgs,
+    mut calendar_vec_deque: &mut VecDeque<Value>,
+    tag: &Tag,
+    selected_year: i32,
+    (start_month, end_month): (u32, u32),
+    current_month: u32,
+    current_day_option: Option<u32>,
+) -> Result<(), ShellError> {
+    for month_number in start_month..=end_month {
+        let mut new_current_day_option: Option<u32> = None;
+
+        if let Some(current_day) = current_day_option {
+            if month_number == current_month {
+                new_current_day_option = Some(current_day)
+            }
+        }
+
+        let add_month_to_table_result = add_month_to_table(
+            &args,
+            &mut calendar_vec_deque,
+            &tag,
+            selected_year,
+            month_number,
+            new_current_day_option,
+        );
+
+        add_month_to_table_result?
+    }
+
+    Ok(())
+}
+
+fn add_month_to_table(
+    args: &EvaluatedWholeStreamCommandArgs,
+    calendar_vec_deque: &mut VecDeque<Value>,
+    tag: &Tag,
+    selected_year: i32,
+    current_month: u32,
+    current_day_option: Option<u32>,
+) -> Result<(), ShellError> {
+    let month_helper_result = MonthHelper::new(selected_year, current_month);
+
+    let month_helper = match month_helper_result {
+        Ok(month_helper) => month_helper,
+        Err(()) => match args.get("full-year") {
+            Some(full_year_value) => {
+                return Err(get_invalid_year_shell_error(&full_year_value.tag()))
+            }
+            None => {
+                return Err(ShellError::labeled_error(
+                    "Issue parsing command",
+                    "invalid command",
+                    tag,
+                ))
+            }
+        },
+    };
+
+    let mut days_of_the_week = [
+        "sunday",
+        "monday",
+        "tuesday",
+        "wednesday",
+        "thursday",
+        "friday",
+        "saturday",
+    ];
+
+    let mut week_start_day = days_of_the_week[0].to_string();
+
+    if let Some(week_start_value) = args.get("week-start") {
+        if let Ok(day) = week_start_value.as_string() {
+            if days_of_the_week.contains(&day.as_str()) {
+                week_start_day = day;
+            } else {
+                return Err(ShellError::labeled_error(
+                    "The specified week start day is invalid",
+                    "invalid week start day",
+                    week_start_value.tag(),
+                ));
+            }
+        }
+    }
+
+    let week_start_day_offset = days_of_the_week.len()
+        - days_of_the_week
+            .iter()
+            .position(|day| *day == week_start_day)
+            .unwrap_or(0);
+
+    days_of_the_week.rotate_right(week_start_day_offset);
+
+    let mut total_start_offset: u32 =
+        month_helper.day_number_of_week_month_starts_on + week_start_day_offset as u32;
+    total_start_offset %= days_of_the_week.len() as u32;
+
+    let mut day_number: u32 = 1;
+    let day_limit: u32 = total_start_offset + month_helper.number_of_days_in_month;
+
+    let should_show_year_column = args.has("year");
+    let should_show_quarter_column = args.has("quarter");
+    let should_show_month_column = args.has("month");
+    let should_show_month_names = args.has("month-names");
+
+    while day_number <= day_limit {
+        let mut indexmap = IndexMap::new();
+
+        if should_show_year_column {
+            indexmap.insert(
+                "year".to_string(),
+                UntaggedValue::int(month_helper.selected_year).into_value(tag),
+            );
+        }
+
+        if should_show_quarter_column {
+            indexmap.insert(
+                "quarter".to_string(),
+                UntaggedValue::int(month_helper.quarter_number).into_value(tag),
+            );
+        }
+
+        if should_show_month_column || should_show_month_names {
+            let month_value = if should_show_month_names {
+                UntaggedValue::string(month_helper.month_name.clone()).into_value(tag)
+            } else {
+                UntaggedValue::int(month_helper.selected_month).into_value(tag)
+            };
+
+            indexmap.insert("month".to_string(), month_value);
+        }
+
+        for day in &days_of_the_week {
+            let should_add_day_number_to_table =
+                (day_number > total_start_offset) && (day_number <= day_limit);
+
+            let mut value = UntaggedValue::nothing().into_value(tag);
+
+            if should_add_day_number_to_table {
+                let adjusted_day_number = day_number - total_start_offset;
+
+                value = UntaggedValue::int(adjusted_day_number).into_value(tag);
+
+                if let Some(current_day) = current_day_option {
+                    if current_day == adjusted_day_number {
+                        // TODO: Update the value here with a color when color support is added
+                        // This colors the current day
+                    }
+                }
+            }
+
+            indexmap.insert((*day).to_string(), value);
+
+            day_number += 1;
+        }
+
+        calendar_vec_deque
+            .push_back(UntaggedValue::Row(Dictionary::from(indexmap)).into_value(tag));
+    }
+
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Cal;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Cal {})?)
+    }
+}

crates/nu-cli/src/commands/calc.rs

@@ -1,63 +0,0 @@
-use crate::commands::PerItemCommand;
-use crate::prelude::*;
-use nu_errors::ShellError;
-use nu_protocol::{CallInfo, Primitive, ReturnSuccess, UntaggedValue, Value};
-
-pub struct Calc;
-
-impl PerItemCommand for Calc {
-    fn name(&self) -> &str {
-        "calc"
-    }
-
-    fn usage(&self) -> &str {
-        "Parse a math expression into a number"
-    }
-
-    fn run(
-        &self,
-        _call_info: &CallInfo,
-        _registry: &CommandRegistry,
-        raw_args: &RawCommandArgs,
-        input: Value,
-    ) -> Result<OutputStream, ShellError> {
-        calc(input, raw_args)
-    }
-}
-
-fn calc(input: Value, args: &RawCommandArgs) -> Result<OutputStream, ShellError> {
-    let name_span = &args.call_info.name_tag.span;
-
-    let output = if let Ok(string) = input.as_string() {
-        match parse(&string, &input.tag) {
-            Ok(value) => ReturnSuccess::value(value),
-            Err(err) => Err(ShellError::labeled_error(
-                "Calculation error",
-                err,
-                &input.tag.span,
-            )),
-        }
-    } else {
-        Err(ShellError::labeled_error(
-            "Expected a string from pipeline",
-            "requires string input",
-            name_span,
-        ))
-    };
-
-    Ok(vec![output].into())
-}
-
-pub fn parse(math_expression: &str, tag: impl Into<Tag>) -> Result<Value, String> {
-    use std::f64;
-    let num = meval::eval_str(math_expression);
-    match num {
-        Ok(num) => {
-            if num == f64::INFINITY || num == f64::NEG_INFINITY {
-                return Err(String::from("cannot represent result"));
-            }
-            Ok(UntaggedValue::from(Primitive::from(num)).into_value(tag))
-        }
-        Err(error) => Err(error.to_string()),
-    }
-}

crates/nu-cli/src/commands/cd.rs

@@ -1,10 +1,20 @@
 use crate::commands::WholeStreamCommand;
 use crate::prelude::*;
+
+use std::path::PathBuf;
+
 use nu_errors::ShellError;
 use nu_protocol::{Signature, SyntaxShape};
+use nu_source::Tagged;
+
+#[derive(Deserialize)]
+pub struct CdArgs {
+    pub(crate) path: Option<Tagged<PathBuf>>,
+}
 
 pub struct Cd;
 
+#[async_trait]
 impl WholeStreamCommand for Cd {
     fn name(&self) -> &str {
         "cd"
@@ -22,17 +32,52 @@ impl WholeStreamCommand for Cd {
         "Change to a new path."
     }
 
-    fn run(
+    async fn run(
         &self,
         args: CommandArgs,
         registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
-        cd(args, registry)
+        let name = args.call_info.name_tag.clone();
+        let shell_manager = args.shell_manager.clone();
+        let (args, _): (CdArgs, _) = args.process(&registry).await?;
+        shell_manager.cd(args, name)
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Change to a new directory called 'dirname'",
+                example: "cd dirname",
+                result: None,
+            },
+            Example {
+                description: "Change to your home directory",
+                example: "cd",
+                result: None,
+            },
+            Example {
+                description: "Change to your home directory (alternate version)",
+                example: "cd ~",
+                result: None,
+            },
+            Example {
+                description: "Change to the previous directory",
+                example: "cd -",
+                result: None,
+            },
+        ]
     }
 }
 
-fn cd(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
-    let shell_manager = args.shell_manager.clone();
-    let args = args.evaluate_once(registry)?;
-    shell_manager.cd(args)
+#[cfg(test)]
+mod tests {
+    use super::Cd;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Cd {})?)
+    }
 }

crates/nu-cli/src/commands/char_.rs

@@ -0,0 +1,170 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
+use nu_source::Tagged;
+
+pub struct Char;
+
+#[derive(Deserialize)]
+struct CharArgs {
+    name: Tagged<String>,
+    unicode: bool,
+}
+
+#[async_trait]
+impl WholeStreamCommand for Char {
+    fn name(&self) -> &str {
+        "char"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("ansi")
+            .required(
+                "character",
+                SyntaxShape::Any,
+                "the name of the character to output",
+            )
+            .switch("unicode", "unicode string i.e. 1f378", Some('u'))
+    }
+
+    fn usage(&self) -> &str {
+        "Output special characters (eg. 'newline')"
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Output newline",
+                example: r#"char newline"#,
+                result: Some(vec![Value::from("\n")]),
+            },
+            Example {
+                description: "Output prompt character, newline and a hamburger character",
+                example: r#"echo $(char prompt) $(char newline) $(char hamburger)"#,
+                result: Some(vec![
+                    UntaggedValue::string("\u{25b6}").into(),
+                    UntaggedValue::string("\n").into(),
+                    UntaggedValue::string("\u{2261}").into(),
+                ]),
+            },
+            Example {
+                description: "Output unicode character",
+                example: r#"char -u 1f378"#,
+                result: Some(vec![Value::from("\u{1f378}")]),
+            },
+        ]
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        let (CharArgs { name, unicode }, _) = args.process(&registry).await?;
+
+        if unicode {
+            let decoded_char = string_to_unicode_char(&name.item);
+            if let Some(output) = decoded_char {
+                Ok(OutputStream::one(ReturnSuccess::value(
+                    UntaggedValue::string(output).into_value(name.tag()),
+                )))
+            } else {
+                Err(ShellError::labeled_error(
+                    "error decoding unicode character",
+                    "error decoding unicode character",
+                    name.tag(),
+                ))
+            }
+        } else {
+            let special_character = str_to_character(&name.item);
+            if let Some(output) = special_character {
+                Ok(OutputStream::one(ReturnSuccess::value(
+                    UntaggedValue::string(output).into_value(name.tag()),
+                )))
+            } else {
+                Err(ShellError::labeled_error(
+                    "error finding named character",
+                    "error finding named character",
+                    name.tag(),
+                ))
+            }
+        }
+    }
+}
+
+fn string_to_unicode_char(s: &str) -> Option<char> {
+    u32::from_str_radix(s, 16)
+        .ok()
+        .and_then(std::char::from_u32)
+}
+
+fn str_to_character(s: &str) -> Option<String> {
+    match s {
+        "newline" | "enter" | "nl" => Some("\n".into()),
+        "tab" => Some("\t".into()),
+        "sp" | "space" => Some(" ".into()),
+        // Unicode names came from https://www.compart.com/en/unicode
+        // Private Use Area (U+E000-U+F8FF)
+        // Unicode can't be mixed with Ansi or it will break width calculation
+        "branch" => Some('\u{e0a0}'.to_string()),  // 
+        "segment" => Some('\u{e0b0}'.to_string()), // 
+
+        "identical_to" | "hamburger" => Some('\u{2261}'.to_string()), // ≡
+        "not_identical_to" | "branch_untracked" => Some('\u{2262}'.to_string()), // ≢
+        "strictly_equivalent_to" | "branch_identical" => Some('\u{2263}'.to_string()), // ≣
+
+        "upwards_arrow" | "branch_ahead" => Some('\u{2191}'.to_string()), // ↑
+        "downwards_arrow" | "branch_behind" => Some('\u{2193}'.to_string()), // ↓
+        "up_down_arrow" | "branch_ahead_behind" => Some('\u{2195}'.to_string()), // ↕
+
+        "black_right_pointing_triangle" | "prompt" => Some('\u{25b6}'.to_string()), // ▶
+        "vector_or_cross_product" | "failed" => Some('\u{2a2f}'.to_string()),       // ⨯
+        "high_voltage_sign" | "elevated" => Some('\u{26a1}'.to_string()),           // ⚡
+        "tilde" | "twiddle" | "squiggly" | "home" => Some("~".into()),              // ~
+        "hash" | "hashtag" | "pound_sign" | "sharp" | "root" => Some("#".into()),   // #
+
+        // Weather symbols
+        "sun" | "sunny" | "sunrise" => Some("☀️".to_string()),
+        "moon" => Some("🌛".to_string()),
+        "cloudy" | "cloud" | "clouds" => Some("☁️".to_string()),
+        "rainy" | "rain" => Some("🌦️".to_string()),
+        "foggy" | "fog" => Some("🌫️".to_string()),
+        "mist" | "haze" => Some("\u{2591}".to_string()),
+        "snowy" | "snow" => Some("❄️".to_string()),
+        "thunderstorm" | "thunder" => Some("🌩️".to_string()),
+
+        // Reference for ansi codes https://gist.github.com/fnky/458719343aabd01cfb17a3a4f7296797
+        // Another good reference http://ascii-table.com/ansi-escape-sequences.php
+
+        // For setting title like `echo [$(char title) $(pwd) $(char bel)] | str collect`
+        "title" => Some("\x1b]2;".to_string()), // ESC]2; xterm sets window title
+        "bel" => Some('\x07'.to_string()),      // Terminal Bell
+        "backspace" => Some('\x08'.to_string()), // Backspace
+
+        // Ansi Erase Sequences
+        "clear_screen" => Some("\x1b[J".to_string()), // clears the screen
+        "clear_screen_from_cursor_to_end" => Some("\x1b[0J".to_string()), // clears from cursor until end of screen
+        "clear_screen_from_cursor_to_beginning" => Some("\x1b[1J".to_string()), // clears from cursor to beginning of screen
+        "cls" | "clear_entire_screen" => Some("\x1b[2J".to_string()), // clears the entire screen
+        "erase_line" => Some("\x1b[K".to_string()),                   // clears the current line
+        "erase_line_from_cursor_to_end" => Some("\x1b[0K".to_string()), // clears from cursor to end of line
+        "erase_line_from_cursor_to_beginning" => Some("\x1b[1K".to_string()), // clears from cursor to start of line
+        "erase_entire_line" => Some("\x1b[2K".to_string()),                   // clears entire line
+
+        _ => None,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Char;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Char {})?)
+    }
+}

crates/nu-cli/src/commands/chart.rs

@@ -0,0 +1,53 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{ReturnSuccess, Signature, UntaggedValue};
+
+#[derive(Clone)]
+pub struct Chart;
+
+#[async_trait]
+impl WholeStreamCommand for Chart {
+    fn name(&self) -> &str {
+        "chart"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("chart")
+    }
+
+    fn usage(&self) -> &str {
+        "Displays charts."
+    }
+
+    async fn run(
+        &self,
+        _args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        if registry.get_command("chart bar").is_none() {
+            return Err(ShellError::untagged_runtime_error(
+                "nu_plugin_chart not installed.",
+            ));
+        }
+
+        let registry = registry.clone();
+        Ok(OutputStream::one(Ok(ReturnSuccess::Value(
+            UntaggedValue::string(crate::commands::help::get_help(&Chart, &registry))
+                .into_value(Tag::unknown()),
+        ))))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Chart;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Chart {})?)
+    }
+}

crates/nu-cli/src/commands/classified/block.rs

@@ -1,7 +1,6 @@
 use crate::commands::classified::expr::run_expression_block;
-//use crate::commands::classified::external::run_external_command;
 use crate::commands::classified::internal::run_internal_command;
-use crate::context::Context;
+use crate::evaluation_context::EvaluationContext;
 use crate::prelude::*;
 use crate::stream::InputStream;
 use futures::stream::TryStreamExt;
@@ -10,11 +9,11 @@ use nu_protocol::hir::{Block, ClassifiedCommand, Commands};
 use nu_protocol::{ReturnSuccess, Scope, UntaggedValue, Value};
 use std::sync::atomic::Ordering;
 
-pub(crate) async fn run_block(
+pub async fn run_block(
     block: &Block,
-    ctx: &mut Context,
+    ctx: &mut EvaluationContext,
     mut input: InputStream,
-    scope: &Scope,
+    scope: Arc<Scope>,
 ) -> Result<InputStream, ShellError> {
     let mut output: Result<InputStream, ShellError> = Ok(InputStream::empty());
     for pipeline in &block.block {
@@ -53,7 +52,7 @@ pub(crate) async fn run_block(
                 return Err(e);
             }
         }
-        output = run_pipeline(pipeline, ctx, input, scope).await;
+        output = run_pipeline(pipeline, ctx, input, scope.clone()).await;
 
         input = InputStream::empty();
     }
@@ -63,32 +62,25 @@ pub(crate) async fn run_block(
 
 async fn run_pipeline(
     commands: &Commands,
-    ctx: &mut Context,
+    ctx: &mut EvaluationContext,
     mut input: InputStream,
-    scope: &Scope,
+    scope: Arc<Scope>,
 ) -> Result<InputStream, ShellError> {
-    let mut iter = commands.list.clone().into_iter().peekable();
-
-    loop {
-        let item: Option<ClassifiedCommand> = iter.next();
-        let next: Option<&ClassifiedCommand> = iter.peek();
-
-        input = match (item, next) {
-            (Some(ClassifiedCommand::Dynamic(_)), _) | (_, Some(ClassifiedCommand::Dynamic(_))) => {
+    for item in commands.list.clone() {
+        input = match item {
+            ClassifiedCommand::Dynamic(_) => {
                 return Err(ShellError::unimplemented("Dynamic commands"))
             }
 
-            (Some(ClassifiedCommand::Expr(expr)), _) => {
-                run_expression_block(*expr, ctx, input, scope)?
-            }
-            (Some(ClassifiedCommand::Error(err)), _) => return Err(err.into()),
-            (_, Some(ClassifiedCommand::Error(err))) => return Err(err.clone().into()),
-
-            (Some(ClassifiedCommand::Internal(left)), _) => {
-                run_internal_command(left, ctx, input, scope)?
+            ClassifiedCommand::Expr(expr) => {
+                run_expression_block(*expr, ctx, scope.clone()).await?
             }
 
-            (None, _) => break,
+            ClassifiedCommand::Error(err) => return Err(err.into()),
+
+            ClassifiedCommand::Internal(left) => {
+                run_internal_command(left, ctx, input, scope.clone()).await?
+            }
         };
     }
 

crates/nu-cli/src/commands/classified/expr.rs

@@ -3,27 +3,23 @@ use crate::prelude::*;
 
 use log::{log_enabled, trace};
 
+use futures::stream::once;
 use nu_errors::ShellError;
 use nu_protocol::hir::SpannedExpression;
 use nu_protocol::Scope;
 
-pub(crate) fn run_expression_block(
+pub(crate) async fn run_expression_block(
     expr: SpannedExpression,
-    context: &mut Context,
-    input: InputStream,
-    scope: &Scope,
+    context: &mut EvaluationContext,
+    scope: Arc<Scope>,
 ) -> Result<InputStream, ShellError> {
     if log_enabled!(log::Level::Trace) {
         trace!(target: "nu::run::expr", "->");
         trace!(target: "nu::run::expr", "{:?}", expr);
     }
 
-    let scope = scope.clone();
     let registry = context.registry().clone();
-    let stream = input.map(move |row| {
-        let scope = scope.clone().set_it(row);
-        evaluate_baseline_expr(&expr, &registry, &scope)
-    });
+    let output = evaluate_baseline_expr(&expr, &registry, scope).await?;
 
-    Ok(stream.to_input_stream())
+    Ok(once(async { Ok(output) }).to_input_stream())
 }

crates/nu-cli/src/commands/classified/external.rs

@@ -1,111 +1,34 @@
+use crate::commands::classified::maybe_text_codec::{MaybeTextCodec, StringOrBinary};
 use crate::evaluate::evaluate_baseline_expr;
 use crate::futures::ThreadedReceiver;
 use crate::prelude::*;
 
+use std::borrow::Cow;
 use std::io::Write;
 use std::ops::Deref;
 use std::process::{Command, Stdio};
 use std::sync::mpsc;
 
-use bytes::{BufMut, Bytes, BytesMut};
 use futures::executor::block_on_stream;
-use futures::stream::StreamExt;
 use futures_codec::FramedRead;
 use log::trace;
 
 use nu_errors::ShellError;
-use nu_protocol::hir::ExternalCommand;
+use nu_protocol::hir::Expression;
+use nu_protocol::hir::{ExternalCommand, ExternalRedirection};
 use nu_protocol::{Primitive, Scope, ShellTypeName, UntaggedValue, Value};
 use nu_source::Tag;
 
-pub enum StringOrBinary {
-    String(String),
-    Binary(Vec<u8>),
-}
-pub struct MaybeTextCodec;
-
-impl futures_codec::Encoder for MaybeTextCodec {
-    type Item = StringOrBinary;
-    type Error = std::io::Error;
-
-    fn encode(&mut self, item: Self::Item, dst: &mut BytesMut) -> Result<(), Self::Error> {
-        match item {
-            StringOrBinary::String(s) => {
-                dst.reserve(s.len());
-                dst.put(s.as_bytes());
-                Ok(())
-            }
-            StringOrBinary::Binary(b) => {
-                dst.reserve(b.len());
-                dst.put(Bytes::from(b));
-                Ok(())
-            }
-        }
-    }
-}
-
-impl futures_codec::Decoder for MaybeTextCodec {
-    type Item = StringOrBinary;
-    type Error = std::io::Error;
-
-    fn decode(&mut self, src: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error> {
-        let v: Vec<u8> = src.to_vec();
-        match String::from_utf8(v) {
-            Ok(s) => {
-                src.clear();
-                if s.is_empty() {
-                    Ok(None)
-                } else {
-                    Ok(Some(StringOrBinary::String(s)))
-                }
-            }
-            Err(err) => {
-                // Note: the longest UTF-8 character per Unicode spec is currently 6 bytes. If we fail somewhere earlier than the last 6 bytes,
-                // we know that we're failing to understand the string encoding and not just seeing a partial character. When this happens, let's
-                // fall back to assuming it's a binary buffer.
-                if src.is_empty() {
-                    Ok(None)
-                } else if src.len() > 6 && (src.len() - err.utf8_error().valid_up_to() > 6) {
-                    // Fall back to assuming binary
-                    let buf = src.to_vec();
-                    src.clear();
-                    Ok(Some(StringOrBinary::Binary(buf)))
-                } else {
-                    // Looks like a utf-8 string, so let's assume that
-                    let buf = src.split_to(err.utf8_error().valid_up_to() + 1);
-                    String::from_utf8(buf.to_vec())
-                        .map(|x| Some(StringOrBinary::String(x)))
-                        .map_err(|e| std::io::Error::new(std::io::ErrorKind::InvalidData, e))
-                }
-            }
-        }
-    }
-}
-
-pub fn nu_value_to_string(name_tag: &Tag, from: &Value) -> Result<String, ShellError> {
-    match &from.value {
-        UntaggedValue::Primitive(Primitive::Int(i)) => Ok(i.to_string()),
-        UntaggedValue::Primitive(Primitive::String(s))
-        | UntaggedValue::Primitive(Primitive::Line(s)) => Ok(s.clone()),
-        UntaggedValue::Primitive(Primitive::Path(p)) => Ok(p.to_string_lossy().to_string()),
-        unsupported => Err(ShellError::labeled_error(
-            format!("needs string data (given: {})", unsupported.type_name()),
-            "expected a string",
-            name_tag,
-        )),
-    }
-}
-
 pub(crate) async fn run_external_command(
     command: ExternalCommand,
-    context: &mut Context,
+    context: &mut EvaluationContext,
     input: InputStream,
-    scope: &Scope,
-    is_last: bool,
+    scope: Arc<Scope>,
+    external_redirection: ExternalRedirection,
 ) -> Result<InputStream, ShellError> {
     trace!(target: "nu::run::external", "-> {}", command.name);
 
-    if !did_find_command(&command.name).await {
+    if !did_find_command(&command.name) {
         return Err(ShellError::labeled_error(
             "Command not found",
             "command not found",
@@ -113,93 +36,15 @@ pub(crate) async fn run_external_command(
         ));
     }
 
-    if command.has_it_argument() {
-        run_with_iterator_arg(command, context, input, scope, is_last)
-    } else {
-        run_with_stdin(command, context, input, scope, is_last)
-    }
+    run_with_stdin(command, context, input, scope, external_redirection).await
 }
 
-fn run_with_iterator_arg(
+async fn run_with_stdin(
     command: ExternalCommand,
-    context: &mut Context,
+    context: &mut EvaluationContext,
     input: InputStream,
-    scope: &Scope,
-    is_last: bool,
-) -> Result<InputStream, ShellError> {
-    let path = context.shell_manager.path();
-
-    let mut inputs: InputStream =
-        trace_stream!(target: "nu::trace_stream::external::it", "input" = input);
-
-    let name_tag = command.name_tag.clone();
-    let scope = scope.clone();
-    let context = context.clone();
-
-    let stream = async_stream! {
-        while let Some(value) = inputs.next().await {
-            // Evaluate the expressions into values, and from values into strings for each iteration
-            let mut command_args = vec![];
-            let scope = scope.clone().set_it(value);
-            for arg in command.args.iter() {
-                let value = evaluate_baseline_expr(arg, &context.registry, &scope)?;
-                command_args.push(nu_value_to_string(&name_tag, &value)?);
-            }
-
-            let process_args = command_args
-            .iter()
-            .map(|arg| {
-                let arg = expand_tilde(arg.deref(), dirs::home_dir);
-
-                #[cfg(not(windows))]
-                {
-                    if argument_contains_whitespace(&arg) && argument_is_quoted(&arg) {
-                        if let Some(unquoted) = remove_quotes(&arg) {
-                            format!(r#""{}""#, unquoted)
-                        } else {
-                            arg.as_ref().to_string()
-                        }
-                    } else {
-                        arg.as_ref().to_string()
-                    }
-                }
-                #[cfg(windows)]
-                {
-                    if let Some(unquoted) = remove_quotes(&arg) {
-                        unquoted.to_string()
-                    } else {
-                        arg.as_ref().to_string()
-                    }
-                }
-            })
-            .collect::<Vec<String>>();
-
-            match spawn(&command, &path, &process_args[..], InputStream::empty(), is_last) {
-                Ok(mut res) => {
-                    while let Some(item) = res.next().await {
-                        yield Ok(item)
-                    }
-                }
-                Err(reason) => {
-                    yield Ok(Value {
-                        value: UntaggedValue::Error(reason),
-                        tag: name_tag
-                    });
-                    return;
-                }
-            }
-        }
-    };
-
-    Ok(stream.to_input_stream())
-}
-
-fn run_with_stdin(
-    command: ExternalCommand,
-    context: &mut Context,
-    input: InputStream,
-    scope: &Scope,
-    is_last: bool,
+    scope: Arc<Scope>,
+    external_redirection: ExternalRedirection,
 ) -> Result<InputStream, ShellError> {
     let path = context.shell_manager.path();
 
@@ -207,19 +52,65 @@ fn run_with_stdin(
 
     let mut command_args = vec![];
     for arg in command.args.iter() {
-        let value = evaluate_baseline_expr(arg, &context.registry, scope)?;
-        command_args.push(value.as_string()?);
+        let is_literal = matches!(arg.expr, Expression::Literal(_));
+        let value = evaluate_baseline_expr(arg, &context.registry, scope.clone()).await?;
+
+        // Skip any arguments that don't really exist, treating them as optional
+        // FIXME: we may want to preserve the gap in the future, though it's hard to say
+        // what value we would put in its place.
+        if value.value.is_none() {
+            continue;
+        }
+
+        // Do the cleanup that we need to do on any argument going out:
+        match &value.value {
+            UntaggedValue::Table(table) => {
+                for t in table {
+                    match &t.value {
+                        UntaggedValue::Primitive(_) => {
+                            command_args.push((
+                                t.convert_to_string().trim_end_matches('\n').to_string(),
+                                is_literal,
+                            ));
+                        }
+                        _ => {
+                            return Err(ShellError::labeled_error(
+                                "Could not convert to positional arguments",
+                                "could not convert to positional arguments",
+                                value.tag(),
+                            ));
+                        }
+                    }
+                }
+            }
+            _ => {
+                let trimmed_value_string = value.as_string()?.trim_end_matches('\n').to_string();
+                command_args.push((trimmed_value_string, is_literal));
+            }
+        }
     }
 
     let process_args = command_args
         .iter()
-        .map(|arg| {
-            let arg = expand_tilde(arg.deref(), dirs::home_dir);
+        .map(|(arg, _is_literal)| {
+            let home_dir;
+
+            #[cfg(feature = "dirs")]
+            {
+                home_dir = dirs::home_dir;
+            }
+            #[cfg(not(feature = "dirs"))]
+            {
+                home_dir = || Some(std::path::PathBuf::from("/"));
+            }
+
+            let arg = expand_tilde(arg.deref(), home_dir);
 
             #[cfg(not(windows))]
             {
-                if argument_contains_whitespace(&arg) && !argument_is_quoted(&arg) {
-                    add_quotes(&arg)
+                if !_is_literal {
+                    let escaped = escape_double_quotes(&arg);
+                    add_double_quotes(&escaped)
                 } else {
                     arg.as_ref().to_string()
                 }
@@ -235,7 +126,14 @@ fn run_with_stdin(
         })
         .collect::<Vec<String>>();
 
-    spawn(&command, &path, &process_args[..], input, is_last)
+    spawn(
+        &command,
+        &path,
+        &process_args[..],
+        input,
+        external_redirection,
+        scope,
+    )
 }
 
 fn spawn(
@@ -243,7 +141,8 @@ fn spawn(
     path: &str,
     args: &[String],
     input: InputStream,
-    is_last: bool,
+    external_redirection: ExternalRedirection,
+    scope: Arc<Scope>,
 ) -> Result<InputStream, ShellError> {
     let command = command.clone();
 
@@ -273,11 +172,27 @@ fn spawn(
     process.current_dir(path);
     trace!(target: "nu::run::external", "cwd = {:?}", &path);
 
+    process.env_clear();
+    process.envs(scope.env());
+
     // We want stdout regardless of what
     // we are doing ($it case or pipe stdin)
-    if !is_last {
-        process.stdout(Stdio::piped());
-        trace!(target: "nu::run::external", "set up stdout pipe");
+    match external_redirection {
+        ExternalRedirection::Stdout => {
+            process.stdout(Stdio::piped());
+            trace!(target: "nu::run::external", "set up stdout pipe");
+        }
+        ExternalRedirection::Stderr => {
+            process.stderr(Stdio::piped());
+            trace!(target: "nu::run::external", "set up stderr pipe");
+        }
+        ExternalRedirection::StdoutAndStderr => {
+            process.stdout(Stdio::piped());
+            trace!(target: "nu::run::external", "set up stdout pipe");
+            process.stderr(Stdio::piped());
+            trace!(target: "nu::run::external", "set up stderr pipe");
+        }
+        _ => {}
     }
 
     // open since we have some contents for stdin
@@ -310,36 +225,19 @@ fn spawn(
                         UntaggedValue::Primitive(Primitive::Nothing) => continue,
                         UntaggedValue::Primitive(Primitive::String(s))
                         | UntaggedValue::Primitive(Primitive::Line(s)) => {
-                            if let Err(e) = stdin_write.write(s.as_bytes()) {
-                                let message = format!("Unable to write to stdin (error = {})", e);
-
-                                let _ = stdin_write_tx.send(Ok(Value {
-                                    value: UntaggedValue::Error(ShellError::labeled_error(
-                                        message,
-                                        "application may have closed before completing pipeline",
-                                        &stdin_name_tag,
-                                    )),
-                                    tag: stdin_name_tag,
-                                }));
-                                return Err(());
+                            if stdin_write.write(s.as_bytes()).is_err() {
+                                // Other side has closed, so exit
+                                return Ok(());
                             }
                         }
                         UntaggedValue::Primitive(Primitive::Binary(b)) => {
-                            if let Err(e) = stdin_write.write(b) {
-                                let message = format!("Unable to write to stdin (error = {})", e);
-
-                                let _ = stdin_write_tx.send(Ok(Value {
-                                    value: UntaggedValue::Error(ShellError::labeled_error(
-                                        message,
-                                        "application may have closed before completing pipeline",
-                                        &stdin_name_tag,
-                                    )),
-                                    tag: stdin_name_tag,
-                                }));
-                                return Err(());
+                            if stdin_write.write(b).is_err() {
+                                // Other side has closed, so exit
+                                return Ok(());
                             }
                         }
                         unsupported => {
+                            println!("Unsupported: {:?}", unsupported);
                             let _ = stdin_write_tx.send(Ok(Value {
                                 value: UntaggedValue::Error(ShellError::labeled_error(
                                     format!(
@@ -361,7 +259,9 @@ fn spawn(
         });
 
         std::thread::spawn(move || {
-            if !is_last {
+            if external_redirection == ExternalRedirection::Stdout
+                || external_redirection == ExternalRedirection::StdoutAndStderr
+            {
                 let stdout = if let Some(stdout) = child.stdout.take() {
                     stdout
                 } else {
@@ -377,7 +277,7 @@ fn spawn(
                 };
 
                 let file = futures::io::AllowStdIo::new(stdout);
-                let stream = FramedRead::new(file, MaybeTextCodec);
+                let stream = FramedRead::new(file, MaybeTextCodec::default());
 
                 for line in block_on_stream(stream) {
                     match line {
@@ -405,16 +305,100 @@ fn spawn(
                                 }
                             }
                         },
-                        Err(_) => {
-                            let _ = stdout_read_tx.send(Ok(Value {
-                                value: UntaggedValue::Error(ShellError::labeled_error(
-                                    "Unable to read from stdout.",
-                                    "unable to read from stdout",
-                                    &stdout_name_tag,
-                                )),
-                                tag: stdout_name_tag.clone(),
-                            }));
-                            break;
+                        Err(e) => {
+                            // If there's an exit status, it makes sense that we may error when
+                            // trying to read from its stdout pipe (likely been closed). In that
+                            // case, don't emit an error.
+                            let should_error = match child.wait() {
+                                Ok(exit_status) => !exit_status.success(),
+                                Err(_) => true,
+                            };
+
+                            if should_error {
+                                let _ = stdout_read_tx.send(Ok(Value {
+                                    value: UntaggedValue::Error(ShellError::labeled_error(
+                                        format!("Unable to read from stdout ({})", e),
+                                        "unable to read from stdout",
+                                        &stdout_name_tag,
+                                    )),
+                                    tag: stdout_name_tag.clone(),
+                                }));
+                            }
+
+                            return Ok(());
+                        }
+                    }
+                }
+            }
+            if external_redirection == ExternalRedirection::Stderr
+                || external_redirection == ExternalRedirection::StdoutAndStderr
+            {
+                let stderr = if let Some(stderr) = child.stderr.take() {
+                    stderr
+                } else {
+                    let _ = stdout_read_tx.send(Ok(Value {
+                        value: UntaggedValue::Error(ShellError::labeled_error(
+                            "Can't redirect the stderr for external command",
+                            "can't redirect stderr",
+                            &stdout_name_tag,
+                        )),
+                        tag: stdout_name_tag,
+                    }));
+                    return Err(());
+                };
+
+                let file = futures::io::AllowStdIo::new(stderr);
+                let stream = FramedRead::new(file, MaybeTextCodec::default());
+
+                for line in block_on_stream(stream) {
+                    match line {
+                        Ok(line) => match line {
+                            StringOrBinary::String(s) => {
+                                let result = stdout_read_tx.send(Ok(Value {
+                                    value: UntaggedValue::Error(
+                                        ShellError::untagged_runtime_error(s),
+                                    ),
+                                    tag: stdout_name_tag.clone(),
+                                }));
+
+                                if result.is_err() {
+                                    break;
+                                }
+                            }
+                            StringOrBinary::Binary(_) => {
+                                let result = stdout_read_tx.send(Ok(Value {
+                                    value: UntaggedValue::Error(
+                                        ShellError::untagged_runtime_error("<binary stderr>"),
+                                    ),
+                                    tag: stdout_name_tag.clone(),
+                                }));
+
+                                if result.is_err() {
+                                    break;
+                                }
+                            }
+                        },
+                        Err(e) => {
+                            // If there's an exit status, it makes sense that we may error when
+                            // trying to read from its stdout pipe (likely been closed). In that
+                            // case, don't emit an error.
+                            let should_error = match child.wait() {
+                                Ok(exit_status) => !exit_status.success(),
+                                Err(_) => true,
+                            };
+
+                            if should_error {
+                                let _ = stdout_read_tx.send(Ok(Value {
+                                    value: UntaggedValue::Error(ShellError::labeled_error(
+                                        format!("Unable to read from stdout ({})", e),
+                                        "unable to read from stdout",
+                                        &stdout_name_tag,
+                                    )),
+                                    tag: stdout_name_tag.clone(),
+                                }));
+                            }
+
+                            return Ok(());
                         }
                     }
                 }
@@ -424,14 +408,11 @@ fn spawn(
             // than what other shells will do.
             let external_failed = match child.wait() {
                 Err(_) => true,
-                Ok(exit_status) => match exit_status.code() {
-                    Some(e) if e != 0 => true,
-                    _ => false,
-                },
+                Ok(exit_status) => !exit_status.success(),
             };
 
             if external_failed {
-                let cfg = crate::data::config::config(Tag::unknown());
+                let cfg = nu_data::config::config(Tag::unknown());
                 if let Ok(cfg) = cfg {
                     if cfg.contains_key("nonzero_exit_errors") {
                         let _ = stdout_read_tx.send(Ok(Value {
@@ -464,21 +445,28 @@ fn spawn(
     }
 }
 
-async fn did_find_command(name: &str) -> bool {
-    #[cfg(not(windows))]
+pub fn did_find_command(#[allow(unused)] name: &str) -> bool {
+    #[cfg(not(feature = "which"))]
     {
-        ichwh::which(name).await.unwrap_or(None).is_some()
+        // we can't perform this check, so just assume it can be found
+        true
     }
 
-    #[cfg(windows)]
+    #[cfg(all(feature = "which", unix))]
     {
-        if ichwh::which(name).await.unwrap_or(None).is_some() {
+        which::which(name).is_ok()
+    }
+
+    #[cfg(all(feature = "which", windows))]
+    {
+        if which::which(name).is_ok() {
             true
         } else {
+            // Reference: https://ss64.com/nt/syntax-internal.html
             let cmd_builtins = [
-                "call", "cls", "color", "date", "dir", "echo", "find", "hostname", "pause",
-                "start", "time", "title", "ver", "copy", "mkdir", "rename", "rd", "rmdir", "type",
-                "mklink",
+                "assoc", "break", "color", "copy", "date", "del", "dir", "dpath", "echo", "erase",
+                "for", "ftype", "md", "mkdir", "mklink", "move", "path", "ren", "rename", "rd",
+                "rmdir", "set", "start", "time", "title", "type", "ver", "verify", "vol",
             ];
 
             cmd_builtins.contains(&name)
@@ -495,11 +483,6 @@ where
     shellexpand::tilde_with_context(input, home_dir)
 }
 
-#[allow(unused)]
-pub fn argument_contains_whitespace(argument: &str) -> bool {
-    argument.chars().any(|c| c.is_whitespace())
-}
-
 fn argument_is_quoted(argument: &str) -> bool {
     if argument.len() < 2 {
         return false;
@@ -510,10 +493,21 @@ fn argument_is_quoted(argument: &str) -> bool {
 }
 
 #[allow(unused)]
-fn add_quotes(argument: &str) -> String {
+fn add_double_quotes(argument: &str) -> String {
     format!("\"{}\"", argument)
 }
 
+#[allow(unused)]
+fn escape_double_quotes(argument: &str) -> Cow<'_, str> {
+    // allocate new string only if required
+    if argument.contains('"') {
+        Cow::Owned(argument.replace('"', r#"\""#))
+    } else {
+        Cow::Borrowed(argument)
+    }
+}
+
+#[allow(unused)]
 fn remove_quotes(argument: &str) -> Option<&str> {
     if !argument_is_quoted(argument) {
         return None;
@@ -538,12 +532,18 @@ fn shell_os_paths() -> Vec<std::path::PathBuf> {
 #[cfg(test)]
 mod tests {
     use super::{
-        add_quotes, argument_contains_whitespace, argument_is_quoted, expand_tilde, remove_quotes,
-        run_external_command, Context, InputStream,
+        add_double_quotes, argument_is_quoted, escape_double_quotes, expand_tilde, remove_quotes,
     };
+    #[cfg(feature = "which")]
+    use super::{run_external_command, EvaluationContext, InputStream};
+
+    #[cfg(feature = "which")]
     use futures::executor::block_on;
+    #[cfg(feature = "which")]
     use nu_errors::ShellError;
+    #[cfg(feature = "which")]
     use nu_protocol::Scope;
+    #[cfg(feature = "which")]
     use nu_test_support::commands::ExternalBuilder;
 
     // async fn read(mut stream: OutputStream) -> Option<Value> {
@@ -559,17 +559,24 @@ mod tests {
     //     }
     // }
 
+    #[cfg(feature = "which")]
     async fn non_existent_run() -> Result<(), ShellError> {
+        use nu_protocol::hir::ExternalRedirection;
         let cmd = ExternalBuilder::for_name("i_dont_exist.exe").build();
 
         let input = InputStream::empty();
-        let mut ctx = Context::basic().expect("There was a problem creating a basic context.");
+        let mut ctx =
+            EvaluationContext::basic().expect("There was a problem creating a basic context.");
 
-        assert!(
-            run_external_command(cmd, &mut ctx, input, &Scope::empty(), false)
-                .await
-                .is_err()
-        );
+        assert!(run_external_command(
+            cmd,
+            &mut ctx,
+            input,
+            Scope::create(),
+            ExternalRedirection::Stdout
+        )
+        .await
+        .is_err());
 
         Ok(())
     }
@@ -577,7 +584,7 @@ mod tests {
     // async fn failure_run() -> Result<(), ShellError> {
     //     let cmd = ExternalBuilder::for_name("fail").build();
 
-    //     let mut ctx = Context::basic().expect("There was a problem creating a basic context.");
+    //     let mut ctx = EvaluationContext::basic().expect("There was a problem creating a basic context.");
     //     let stream = run_external_command(cmd, &mut ctx, None, false)
     //         .await?
     //         .expect("There was a problem running the external command.");
@@ -598,16 +605,17 @@ mod tests {
     //     block_on(failure_run())
     // }
 
+    #[cfg(feature = "which")]
     #[test]
     fn identifies_command_not_found() -> Result<(), ShellError> {
         block_on(non_existent_run())
     }
 
     #[test]
-    fn checks_contains_whitespace_from_argument_to_be_passed_in() {
-        assert_eq!(argument_contains_whitespace("andrés"), false);
-        assert_eq!(argument_contains_whitespace("and rés"), true);
-        assert_eq!(argument_contains_whitespace(r#"and\ rés"#), true);
+    fn checks_escape_double_quotes() {
+        assert_eq!(escape_double_quotes("andrés"), "andrés");
+        assert_eq!(escape_double_quotes(r#"an"drés"#), r#"an\"drés"#);
+        assert_eq!(escape_double_quotes(r#""an"drés""#), r#"\"an\"drés\""#);
     }
 
     #[test]
@@ -635,9 +643,8 @@ mod tests {
     }
 
     #[test]
-    fn adds_quotes_to_argument_to_be_passed_in() {
-        assert_eq!(add_quotes("andrés"), "\"andrés\"");
-        //assert_eq!(add_quotes("\"andrés\""), "\"andrés\"");
+    fn adds_double_quotes_to_argument_to_be_passed_in() {
+        assert_eq!(add_double_quotes("andrés"), "\"andrés\"");
     }
 
     #[test]

crates/nu-cli/src/commands/classified/internal.rs

@@ -1,17 +1,17 @@
-use crate::commands::command::per_item_command;
+use crate::commands::command::whole_stream_command;
 use crate::commands::run_alias::AliasCommand;
 use crate::commands::UnevaluatedCallInfo;
 use crate::prelude::*;
 use log::{log_enabled, trace};
 use nu_errors::ShellError;
-use nu_protocol::hir::InternalCommand;
+use nu_protocol::hir::{ExternalRedirection, InternalCommand};
 use nu_protocol::{CommandAction, Primitive, ReturnSuccess, Scope, UntaggedValue, Value};
 
-pub(crate) fn run_internal_command(
+pub(crate) async fn run_internal_command(
     command: InternalCommand,
-    context: &mut Context,
+    context: &mut EvaluationContext,
     input: InputStream,
-    scope: &Scope,
+    scope: Arc<Scope>,
 ) -> Result<InputStream, ShellError> {
     if log_enabled!(log::Level::Trace) {
         trace!(target: "nu::run::internal", "->");
@@ -21,165 +21,247 @@ pub(crate) fn run_internal_command(
     let objects: InputStream = trace_stream!(target: "nu::trace_stream::internal", "input" = input);
     let internal_command = context.expect_command(&command.name);
 
+    if command.name == "autoenv untrust" {
+        context.user_recently_used_autoenv_untrust = true;
+    }
+
     let result = {
-        context.run_command(
-            internal_command?,
-            Tag::unknown_anchor(command.name_span),
-            command.args.clone(),
-            scope,
-            objects,
-        )
+        context
+            .run_command(
+                internal_command?,
+                Tag::unknown_anchor(command.name_span),
+                command.args.clone(),
+                scope.clone(),
+                objects,
+            )
+            .await?
     };
 
-    let mut result = trace_out_stream!(target: "nu::trace_stream::internal", "output" = result);
-    let mut context = context.clone();
+    let head = Arc::new(command.args.head.clone());
+    //let context = Arc::new(context.clone());
+    let context = context.clone();
+    let command = Arc::new(command);
 
-    let stream = async_stream! {
-        let mut soft_errs: Vec<ShellError> = vec![];
-        let mut yielded = false;
+    Ok(InputStream::from_stream(
+        result
+            .then(move |item| {
+                let head = head.clone();
+                let command = command.clone();
+                let mut context = context.clone();
+                let scope = scope.clone();
+                async move {
+                    match item {
+                        Ok(ReturnSuccess::Action(action)) => match action {
+                            CommandAction::ChangePath(path) => {
+                                context.shell_manager.set_path(path);
+                                InputStream::from_stream(futures::stream::iter(vec![]))
+                            }
+                            CommandAction::Exit => std::process::exit(0), // TODO: save history.txt
+                            CommandAction::Error(err) => {
+                                context.error(err.clone());
+                                InputStream::one(UntaggedValue::Error(err).into_untagged_value())
+                            }
+                            CommandAction::AutoConvert(tagged_contents, extension) => {
+                                let contents_tag = tagged_contents.tag.clone();
+                                let command_name = format!("from {}", extension);
+                                let command = command.clone();
+                                if let Some(converter) = context.registry.get_command(&command_name)
+                                {
+                                    let new_args = RawCommandArgs {
+                                        host: context.host.clone(),
+                                        ctrl_c: context.ctrl_c.clone(),
+                                        current_errors: context.current_errors.clone(),
+                                        shell_manager: context.shell_manager.clone(),
+                                        call_info: UnevaluatedCallInfo {
+                                            args: nu_protocol::hir::Call {
+                                                head: (&*head).clone(),
+                                                positional: None,
+                                                named: None,
+                                                span: Span::unknown(),
+                                                external_redirection: ExternalRedirection::Stdout,
+                                            },
+                                            name_tag: Tag::unknown_anchor(command.name_span),
+                                            scope,
+                                        },
+                                    };
+                                    let result = converter
+                                        .run(
+                                            new_args.with_input(vec![tagged_contents]),
+                                            &context.registry,
+                                        )
+                                        .await;
 
-        while let Some(item) = result.next().await {
-            match item {
-                Ok(ReturnSuccess::Action(action)) => match action {
-                    CommandAction::ChangePath(path) => {
-                        context.shell_manager.set_path(path);
-                    }
-                    CommandAction::Exit => std::process::exit(0), // TODO: save history.txt
-                    CommandAction::Error(err) => {
-                        context.error(err);
-                        break;
-                    }
-                    CommandAction::AutoConvert(tagged_contents, extension) => {
-                        let contents_tag = tagged_contents.tag.clone();
-                        let command_name = format!("from-{}", extension);
-                        let command = command.clone();
-                        if let Some(converter) = context.registry.get_command(&command_name) {
-                            let new_args = RawCommandArgs {
-                                host: context.host.clone(),
-                                ctrl_c: context.ctrl_c.clone(),
-                                shell_manager: context.shell_manager.clone(),
-                                call_info: UnevaluatedCallInfo {
-                                    args: nu_protocol::hir::Call {
-                                        head: command.args.head,
-                                        positional: None,
-                                        named: None,
-                                        span: Span::unknown(),
-                                        is_last: false,
-                                    },
-                                    name_tag: Tag::unknown_anchor(command.name_span),
-                                    scope: Scope::empty(),
-                                }
-                            };
-                            let mut result = converter.run(new_args.with_input(vec![tagged_contents]), &context.registry);
-                            let result_vec: Vec<Result<ReturnSuccess, ShellError>> = result.drain_vec().await;
-                            for res in result_vec {
-                                match res {
-                                    Ok(ReturnSuccess::Value(Value { value: UntaggedValue::Table(list), ..})) => {
-                                        for l in list {
-                                            yield Ok(l);
+                                    match result {
+                                        Ok(mut result) => {
+                                            let result_vec: Vec<Result<ReturnSuccess, ShellError>> =
+                                                result.drain_vec().await;
+
+                                            let mut output = vec![];
+                                            for res in result_vec {
+                                                match res {
+                                                    Ok(ReturnSuccess::Value(Value {
+                                                        value: UntaggedValue::Table(list),
+                                                        ..
+                                                    })) => {
+                                                        for l in list {
+                                                            output.push(Ok(l));
+                                                        }
+                                                    }
+                                                    Ok(ReturnSuccess::Value(Value {
+                                                        value,
+                                                        ..
+                                                    })) => {
+                                                        output
+                                                            .push(Ok(value
+                                                                .into_value(contents_tag.clone())));
+                                                    }
+                                                    Err(e) => output.push(Err(e)),
+                                                    _ => {}
+                                                }
+                                            }
+
+                                            futures::stream::iter(output).to_input_stream()
+                                        }
+                                        Err(e) => {
+                                            context.add_error(e);
+                                            InputStream::empty()
                                         }
                                     }
-                                    Ok(ReturnSuccess::Value(Value { value, .. })) => {
-                                        yield Ok(value.into_value(contents_tag.clone()));
-                                    }
-                                    Err(e) => yield Err(e),
-                                    _ => {}
+                                } else {
+                                    InputStream::one(tagged_contents)
                                 }
                             }
-                        } else {
-                            yield Ok(tagged_contents)
-                        }
-                    }
-                    CommandAction::EnterHelpShell(value) => {
-                        match value {
-                            Value {
-                                value: UntaggedValue::Primitive(Primitive::String(cmd)),
-                                tag,
-                            } => {
-                                context.shell_manager.insert_at_current(Box::new(
-                                    HelpShell::for_command(
-                                        UntaggedValue::string(cmd).into_value(tag),
-                                        &context.registry(),
-                                    )?,
-                                ));
+                            CommandAction::EnterHelpShell(value) => match value {
+                                Value {
+                                    value: UntaggedValue::Primitive(Primitive::String(cmd)),
+                                    tag,
+                                } => {
+                                    context.shell_manager.insert_at_current(Box::new(
+                                        match HelpShell::for_command(
+                                            UntaggedValue::string(cmd).into_value(tag),
+                                            &context.registry(),
+                                        ) {
+                                            Ok(v) => v,
+                                            Err(err) => {
+                                                return InputStream::one(
+                                                    UntaggedValue::Error(err).into_untagged_value(),
+                                                )
+                                            }
+                                        },
+                                    ));
+                                    InputStream::from_stream(futures::stream::iter(vec![]))
+                                }
+                                _ => {
+                                    context.shell_manager.insert_at_current(Box::new(
+                                        match HelpShell::index(&context.registry()) {
+                                            Ok(v) => v,
+                                            Err(err) => {
+                                                return InputStream::one(
+                                                    UntaggedValue::Error(err).into_untagged_value(),
+                                                )
+                                            }
+                                        },
+                                    ));
+                                    InputStream::from_stream(futures::stream::iter(vec![]))
+                                }
+                            },
+                            CommandAction::EnterValueShell(value) => {
+                                context
+                                    .shell_manager
+                                    .insert_at_current(Box::new(ValueShell::new(value)));
+                                InputStream::from_stream(futures::stream::iter(vec![]))
                             }
-                            _ => {
+                            CommandAction::EnterShell(location) => {
                                 context.shell_manager.insert_at_current(Box::new(
-                                    HelpShell::index(&context.registry())?,
+                                    match FilesystemShell::with_location(location) {
+                                        Ok(v) => v,
+                                        Err(err) => {
+                                            return InputStream::one(
+                                                UntaggedValue::Error(err.into())
+                                                    .into_untagged_value(),
+                                            )
+                                        }
+                                    },
                                 ));
+                                InputStream::from_stream(futures::stream::iter(vec![]))
                             }
+                            CommandAction::AddAlias(sig, block) => {
+                                context.add_commands(vec![whole_stream_command(
+                                    AliasCommand::new(*sig, block),
+                                )]);
+                                InputStream::from_stream(futures::stream::iter(vec![]))
+                            }
+                            CommandAction::AddPlugins(path) => {
+                                match crate::plugin::scan(vec![std::path::PathBuf::from(path)]) {
+                                    Ok(plugins) => {
+                                        context.add_commands(
+                                            plugins
+                                                .into_iter()
+                                                .filter(|p| {
+                                                    !context.is_command_registered(p.name())
+                                                })
+                                                .collect(),
+                                        );
+
+                                        InputStream::from_stream(futures::stream::iter(vec![]))
+                                    }
+                                    Err(reason) => {
+                                        context.error(reason.clone());
+                                        InputStream::one(
+                                            UntaggedValue::Error(reason).into_untagged_value(),
+                                        )
+                                    }
+                                }
+                            }
+                            CommandAction::PreviousShell => {
+                                context.shell_manager.prev();
+                                InputStream::from_stream(futures::stream::iter(vec![]))
+                            }
+                            CommandAction::NextShell => {
+                                context.shell_manager.next();
+                                InputStream::from_stream(futures::stream::iter(vec![]))
+                            }
+                            CommandAction::LeaveShell => {
+                                context.shell_manager.remove_at_current();
+                                if context.shell_manager.is_empty() {
+                                    std::process::exit(0); // TODO: save history.txt
+                                }
+                                InputStream::from_stream(futures::stream::iter(vec![]))
+                            }
+                        },
+
+                        Ok(ReturnSuccess::Value(Value {
+                            value: UntaggedValue::Error(err),
+                            tag,
+                        })) => {
+                            context.error(err.clone());
+                            InputStream::one(UntaggedValue::Error(err).into_value(tag))
+                        }
+
+                        Ok(ReturnSuccess::Value(v)) => InputStream::one(v),
+
+                        Ok(ReturnSuccess::DebugValue(v)) => {
+                            let doc = PrettyDebug::pretty_doc(&v);
+                            let mut buffer = termcolor::Buffer::ansi();
+
+                            let _ = doc.render_raw(
+                                context.with_host(|host| host.width() - 5),
+                                &mut nu_source::TermColored::new(&mut buffer),
+                            );
+
+                            let value = String::from_utf8_lossy(buffer.as_slice());
+
+                            InputStream::one(UntaggedValue::string(value).into_untagged_value())
+                        }
+
+                        Err(err) => {
+                            context.error(err.clone());
+                            InputStream::one(UntaggedValue::Error(err).into_untagged_value())
                         }
                     }
-                    CommandAction::EnterValueShell(value) => {
-                        context
-                            .shell_manager
-                            .insert_at_current(Box::new(ValueShell::new(value)));
-                    }
-                    CommandAction::EnterShell(location) => {
-                        context.shell_manager.insert_at_current(Box::new(
-                            FilesystemShell::with_location(location, context.registry().clone()),
-                        ));
-                    }
-                    CommandAction::AddAlias(name, args, block) => {
-                        context.add_commands(vec![
-                            per_item_command(AliasCommand::new(
-                                name,
-                                args,
-                                block,
-                            ))
-                        ]);
-                    }
-                    CommandAction::PreviousShell => {
-                        context.shell_manager.prev();
-                    }
-                    CommandAction::NextShell => {
-                        context.shell_manager.next();
-                    }
-                    CommandAction::LeaveShell => {
-                        context.shell_manager.remove_at_current();
-                        if context.shell_manager.is_empty() {
-                            std::process::exit(0); // TODO: save history.txt
-                        }
-                    }
-                },
-
-                Ok(ReturnSuccess::Value(Value {
-                    value: UntaggedValue::Error(err),
-                    ..
-                })) => {
-                    context.error(err.clone());
-                    yield Err(err);
-                    break;
                 }
-
-                Ok(ReturnSuccess::Value(v)) => {
-                    yielded = true;
-                    yield Ok(v);
-                }
-
-                Ok(ReturnSuccess::DebugValue(v)) => {
-                    yielded = true;
-
-                    let doc = PrettyDebug::pretty_doc(&v);
-                    let mut buffer = termcolor::Buffer::ansi();
-
-                    let _ = doc.render_raw(
-                        context.with_host(|host| host.width() - 5),
-                        &mut nu_source::TermColored::new(&mut buffer),
-                    );
-
-                    let value = String::from_utf8_lossy(buffer.as_slice());
-
-                    yield Ok(UntaggedValue::string(value).into_untagged_value())
-                }
-
-                Err(err) => {
-                    context.error(err);
-                    break;
-                }
-            }
-        }
-    };
-
-    Ok(stream.to_input_stream())
+            })
+            .flatten()
+            .take_while(|x| futures::future::ready(!x.is_error())),
+    ))
 }

crates/nu-cli/src/commands/classified/maybe_text_codec.rs

@@ -0,0 +1,127 @@
+use bytes::{BufMut, Bytes, BytesMut};
+
+use nu_errors::ShellError;
+
+extern crate encoding_rs;
+use encoding_rs::{CoderResult, Decoder, Encoding, UTF_8};
+
+#[cfg(not(test))]
+const OUTPUT_BUFFER_SIZE: usize = 8192;
+#[cfg(test)]
+const OUTPUT_BUFFER_SIZE: usize = 4;
+
+#[derive(Debug, Eq, PartialEq)]
+pub enum StringOrBinary {
+    String(String),
+    Binary(Vec<u8>),
+}
+
+pub struct MaybeTextCodec {
+    decoder: Decoder,
+}
+
+impl MaybeTextCodec {
+    // The constructor takes an Option<&'static Encoding>, because an absence of an encoding indicates that we want BOM sniffing enabled
+    pub fn new(encoding: Option<&'static Encoding>) -> Self {
+        let decoder = match encoding {
+            Some(e) => e.new_decoder_with_bom_removal(),
+            None => UTF_8.new_decoder(),
+        };
+        MaybeTextCodec { decoder }
+    }
+}
+
+impl Default for MaybeTextCodec {
+    fn default() -> Self {
+        MaybeTextCodec {
+            decoder: UTF_8.new_decoder(),
+        }
+    }
+}
+
+impl futures_codec::Encoder for MaybeTextCodec {
+    type Item = StringOrBinary;
+    type Error = std::io::Error;
+
+    fn encode(&mut self, item: Self::Item, dst: &mut BytesMut) -> Result<(), Self::Error> {
+        match item {
+            StringOrBinary::String(s) => {
+                dst.reserve(s.len());
+                dst.put(s.as_bytes());
+                Ok(())
+            }
+            StringOrBinary::Binary(b) => {
+                dst.reserve(b.len());
+                dst.put(Bytes::from(b));
+                Ok(())
+            }
+        }
+    }
+}
+
+impl futures_codec::Decoder for MaybeTextCodec {
+    type Item = StringOrBinary;
+    type Error = ShellError;
+
+    fn decode(&mut self, src: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error> {
+        if src.is_empty() {
+            return Ok(None);
+        }
+
+        let mut s = String::with_capacity(OUTPUT_BUFFER_SIZE);
+
+        let (res, _read, replacements) = self.decoder.decode_to_string(src, &mut s, false);
+
+        let result = if replacements {
+            // If we had to make replacements when converting to utf8, fall back to binary
+            StringOrBinary::Binary(src.to_vec())
+        } else {
+            // If original buffer size is too small, we continue to allocate new Strings and append
+            // them to the result until the input buffer is smaller than the allocated String
+            if let CoderResult::OutputFull = res {
+                let mut buffer = String::with_capacity(OUTPUT_BUFFER_SIZE);
+                loop {
+                    let (res, _read, _replacements) =
+                        self.decoder
+                            .decode_to_string(&src[s.len()..], &mut buffer, false);
+                    s.push_str(&buffer);
+
+                    if let CoderResult::InputEmpty = res {
+                        break;
+                    }
+
+                    buffer.clear();
+                }
+            }
+
+            StringOrBinary::String(s)
+        };
+
+        src.clear();
+
+        Ok(Some(result))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{MaybeTextCodec, StringOrBinary};
+    use bytes::BytesMut;
+    use futures_codec::Decoder;
+
+    // TODO: Write some more tests
+
+    #[test]
+    fn should_consume_all_bytes_from_source_when_temporary_buffer_overflows() {
+        let mut maybe_text = MaybeTextCodec::new(None);
+        let mut bytes = BytesMut::from("0123456789");
+
+        let text = maybe_text.decode(&mut bytes);
+
+        assert_eq!(
+            Ok(Some(StringOrBinary::String("0123456789".to_string()))),
+            text
+        );
+        assert!(bytes.is_empty());
+    }
+}

crates/nu-cli/src/commands/classified/mod.rs

@@ -3,6 +3,8 @@ mod dynamic;
 pub(crate) mod expr;
 pub(crate) mod external;
 pub(crate) mod internal;
+pub(crate) mod maybe_text_codec;
+pub(crate) mod plugin;
 
 #[allow(unused_imports)]
 pub(crate) use dynamic::Command as DynamicCommand;

crates/nu-cli/src/commands/classified/plugin.rs

@@ -0,0 +1,467 @@
+use crate::commands::command::{whole_stream_command, WholeStreamCommand};
+use crate::prelude::*;
+use derive_new::new;
+use log::trace;
+use nu_errors::ShellError;
+use nu_plugin::jsonrpc::JsonRpc;
+use nu_protocol::{Primitive, ReturnValue, Signature, UntaggedValue, Value};
+use serde::{self, Deserialize, Serialize};
+use std::io::prelude::*;
+use std::io::BufReader;
+use std::io::Write;
+use std::path::Path;
+use std::process::{Child, Command, Stdio};
+
+#[derive(Debug, Serialize, Deserialize)]
+#[serde(tag = "method")]
+#[allow(non_camel_case_types)]
+pub enum NuResult {
+    response {
+        params: Result<VecDeque<ReturnValue>, ShellError>,
+    },
+}
+
+enum PluginCommand {
+    Filter(PluginFilter),
+    Sink(PluginSink),
+}
+
+impl PluginCommand {
+    fn command(self) -> Result<crate::commands::Command, ShellError> {
+        match self {
+            PluginCommand::Filter(cmd) => Ok(whole_stream_command(cmd)),
+            PluginCommand::Sink(cmd) => Ok(whole_stream_command(cmd)),
+        }
+    }
+}
+
+enum PluginMode {
+    Filter,
+    Sink,
+}
+
+pub struct PluginCommandBuilder {
+    mode: PluginMode,
+    name: String,
+    path: String,
+    config: Signature,
+}
+
+impl PluginCommandBuilder {
+    pub fn new(
+        name: impl Into<String>,
+        path: impl Into<String>,
+        config: impl Into<Signature>,
+    ) -> Self {
+        let config = config.into();
+
+        PluginCommandBuilder {
+            mode: if config.is_filter {
+                PluginMode::Filter
+            } else {
+                PluginMode::Sink
+            },
+            name: name.into(),
+            path: path.into(),
+            config,
+        }
+    }
+
+    pub fn build(&self) -> Result<crate::commands::Command, ShellError> {
+        let mode = &self.mode;
+
+        let name = self.name.clone();
+        let path = self.path.clone();
+        let config = self.config.clone();
+
+        let cmd = match mode {
+            PluginMode::Filter => PluginCommand::Filter(PluginFilter { name, path, config }),
+            PluginMode::Sink => PluginCommand::Sink(PluginSink { name, path, config }),
+        };
+
+        cmd.command()
+    }
+}
+
+#[derive(new)]
+pub struct PluginFilter {
+    name: String,
+    path: String,
+    config: Signature,
+}
+
+#[async_trait]
+impl WholeStreamCommand for PluginFilter {
+    fn name(&self) -> &str {
+        &self.name
+    }
+
+    fn signature(&self) -> Signature {
+        self.config.clone()
+    }
+
+    fn usage(&self) -> &str {
+        &self.config.usage
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        run_filter(self.path.clone(), args, registry).await
+    }
+}
+
+async fn run_filter(
+    path: String,
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    trace!("filter_plugin :: {}", path);
+    let registry = registry.clone();
+
+    let scope = args.call_info.scope.clone();
+
+    let bos = futures::stream::iter(vec![
+        UntaggedValue::Primitive(Primitive::BeginningOfStream).into_untagged_value()
+    ]);
+    let eos = futures::stream::iter(vec![
+        UntaggedValue::Primitive(Primitive::EndOfStream).into_untagged_value()
+    ]);
+
+    let args = args.evaluate_once_with_scope(&registry, scope).await?;
+
+    let real_path = Path::new(&path);
+    let ext = real_path.extension();
+    let ps1_file = match ext {
+        Some(ext) => ext == "ps1",
+        None => false,
+    };
+
+    let mut child: Child = if ps1_file {
+        Command::new("pwsh")
+            .stdin(Stdio::piped())
+            .stdout(Stdio::piped())
+            .args(&[
+                "-NoLogo",
+                "-NoProfile",
+                "-ExecutionPolicy",
+                "Bypass",
+                "-File",
+                &real_path.to_string_lossy(),
+            ])
+            .spawn()
+            .expect("Failed to spawn PowerShell process")
+    } else {
+        Command::new(path)
+            .stdin(Stdio::piped())
+            .stdout(Stdio::piped())
+            .spawn()
+            .expect("Failed to spawn child process")
+    };
+
+    let call_info = args.call_info.clone();
+
+    trace!("filtering :: {:?}", call_info);
+
+    Ok(bos
+        .chain(args.input)
+        .chain(eos)
+        .map(move |item| {
+            match item {
+                Value {
+                    value: UntaggedValue::Primitive(Primitive::BeginningOfStream),
+                    ..
+                } => {
+                    // Beginning of the stream
+                    let stdin = child.stdin.as_mut().expect("Failed to open stdin");
+                    let stdout = child.stdout.as_mut().expect("Failed to open stdout");
+
+                    let mut reader = BufReader::new(stdout);
+
+                    let request = JsonRpc::new("begin_filter", call_info.clone());
+                    let request_raw = serde_json::to_string(&request);
+                    trace!("begin_filter:request {:?}", &request_raw);
+
+                    match request_raw {
+                        Err(_) => {
+                            return OutputStream::one(Err(ShellError::labeled_error(
+                                "Could not load json from plugin",
+                                "could not load json from plugin",
+                                &call_info.name_tag,
+                            )));
+                        }
+                        Ok(request_raw) => {
+                            match stdin.write(format!("{}\n", request_raw).as_bytes()) {
+                                Ok(_) => {}
+                                Err(err) => {
+                                    return OutputStream::one(Err(ShellError::unexpected(
+                                        format!("{}", err),
+                                    )));
+                                }
+                            }
+                        }
+                    }
+
+                    let mut input = String::new();
+                    match reader.read_line(&mut input) {
+                        Ok(_) => {
+                            let response = serde_json::from_str::<NuResult>(&input);
+                            trace!("begin_filter:response {:?}", &response);
+
+                            match response {
+                                Ok(NuResult::response { params }) => match params {
+                                    Ok(params) => futures::stream::iter(params).to_output_stream(),
+                                    Err(e) => futures::stream::iter(vec![ReturnValue::Err(e)])
+                                        .to_output_stream(),
+                                },
+
+                                Err(e) => OutputStream::one(Err(
+                                    ShellError::untagged_runtime_error(format!(
+                                        "Error while processing begin_filter response: {:?} {}",
+                                        e, input
+                                    )),
+                                )),
+                            }
+                        }
+                        Err(e) => OutputStream::one(Err(ShellError::untagged_runtime_error(
+                            format!("Error while reading begin_filter response: {:?}", e),
+                        ))),
+                    }
+                }
+                Value {
+                    value: UntaggedValue::Primitive(Primitive::EndOfStream),
+                    ..
+                } => {
+                    // post stream contents
+                    let stdin = child.stdin.as_mut().expect("Failed to open stdin");
+                    let stdout = child.stdout.as_mut().expect("Failed to open stdout");
+
+                    let mut reader = BufReader::new(stdout);
+
+                    let request: JsonRpc<std::vec::Vec<Value>> = JsonRpc::new("end_filter", vec![]);
+                    let request_raw = serde_json::to_string(&request);
+                    trace!("end_filter:request {:?}", &request_raw);
+
+                    match request_raw {
+                        Err(_) => {
+                            return OutputStream::one(Err(ShellError::labeled_error(
+                                "Could not load json from plugin",
+                                "could not load json from plugin",
+                                &call_info.name_tag,
+                            )));
+                        }
+                        Ok(request_raw) => {
+                            match stdin.write(format!("{}\n", request_raw).as_bytes()) {
+                                Ok(_) => {}
+                                Err(err) => {
+                                    return OutputStream::one(Err(ShellError::unexpected(
+                                        format!("{}", err),
+                                    )));
+                                }
+                            }
+                        }
+                    }
+
+                    let mut input = String::new();
+                    let stream = match reader.read_line(&mut input) {
+                        Ok(_) => {
+                            let response = serde_json::from_str::<NuResult>(&input);
+                            trace!("end_filter:response {:?}", &response);
+
+                            match response {
+                                Ok(NuResult::response { params }) => match params {
+                                    Ok(params) => futures::stream::iter(params).to_output_stream(),
+                                    Err(e) => futures::stream::iter(vec![ReturnValue::Err(e)])
+                                        .to_output_stream(),
+                                },
+                                Err(e) => futures::stream::iter(vec![Err(
+                                    ShellError::untagged_runtime_error(format!(
+                                        "Error while processing end_filter response: {:?} {}",
+                                        e, input
+                                    )),
+                                )])
+                                .to_output_stream(),
+                            }
+                        }
+                        Err(e) => {
+                            futures::stream::iter(vec![Err(ShellError::untagged_runtime_error(
+                                format!("Error while reading end_filter response: {:?}", e),
+                            ))])
+                            .to_output_stream()
+                        }
+                    };
+
+                    let stdin = child.stdin.as_mut().expect("Failed to open stdin");
+
+                    let request: JsonRpc<std::vec::Vec<Value>> = JsonRpc::new("quit", vec![]);
+                    let request_raw = serde_json::to_string(&request);
+                    trace!("quit:request {:?}", &request_raw);
+
+                    match request_raw {
+                        Ok(request_raw) => {
+                            let _ = stdin.write(format!("{}\n", request_raw).as_bytes());
+                            // TODO: Handle error
+                        }
+                        Err(e) => {
+                            return OutputStream::one(Err(ShellError::untagged_runtime_error(
+                                format!("Error while processing quit response: {:?}", e),
+                            )));
+                        }
+                    }
+                    let _ = child.wait();
+
+                    stream
+                }
+
+                v => {
+                    // Stream contents
+                    let stdin = child.stdin.as_mut().expect("Failed to open stdin");
+                    let stdout = child.stdout.as_mut().expect("Failed to open stdout");
+
+                    let mut reader = BufReader::new(stdout);
+
+                    let request = JsonRpc::new("filter", v);
+                    let request_raw = serde_json::to_string(&request);
+                    trace!("filter:request {:?}", &request_raw);
+
+                    match request_raw {
+                        Ok(request_raw) => {
+                            let _ = stdin.write(format!("{}\n", request_raw).as_bytes());
+                            // TODO: Handle error
+                        }
+                        Err(e) => {
+                            return OutputStream::one(Err(ShellError::untagged_runtime_error(
+                                format!("Error while processing filter response: {:?}", e),
+                            )));
+                        }
+                    }
+
+                    let mut input = String::new();
+                    match reader.read_line(&mut input) {
+                        Ok(_) => {
+                            let response = serde_json::from_str::<NuResult>(&input);
+                            trace!("filter:response {:?}", &response);
+
+                            match response {
+                                Ok(NuResult::response { params }) => match params {
+                                    Ok(params) => futures::stream::iter(params).to_output_stream(),
+                                    Err(e) => futures::stream::iter(vec![ReturnValue::Err(e)])
+                                        .to_output_stream(),
+                                },
+                                Err(e) => OutputStream::one(Err(
+                                    ShellError::untagged_runtime_error(format!(
+                                    "Error while processing filter response: {:?}\n== input ==\n{}",
+                                    e, input
+                                )),
+                                )),
+                            }
+                        }
+                        Err(e) => OutputStream::one(Err(ShellError::untagged_runtime_error(
+                            format!("Error while reading filter response: {:?}", e),
+                        ))),
+                    }
+                }
+            }
+        })
+        .flatten()
+        .to_output_stream())
+}
+
+#[derive(new)]
+pub struct PluginSink {
+    name: String,
+    path: String,
+    config: Signature,
+}
+
+#[async_trait]
+impl WholeStreamCommand for PluginSink {
+    fn name(&self) -> &str {
+        &self.name
+    }
+
+    fn signature(&self) -> Signature {
+        self.config.clone()
+    }
+
+    fn usage(&self) -> &str {
+        &self.config.usage
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        run_sink(self.path.clone(), args, registry).await
+    }
+}
+
+async fn run_sink(
+    path: String,
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+    let args = args.evaluate_once(&registry).await?;
+    let call_info = args.call_info.clone();
+
+    let input: Vec<Value> = args.input.collect().await;
+
+    let request = JsonRpc::new("sink", (call_info.clone(), input));
+    let request_raw = serde_json::to_string(&request);
+    if let Ok(request_raw) = request_raw {
+        if let Ok(mut tmpfile) = tempfile::NamedTempFile::new() {
+            let _ = writeln!(tmpfile, "{}", request_raw);
+            let _ = tmpfile.flush();
+
+            let real_path = Path::new(&path);
+            let ext = real_path.extension();
+            let ps1_file = match ext {
+                Some(ext) => ext == "ps1",
+                None => false,
+            };
+
+            // TODO: This sink may not work in powershell, trying to find
+            // an example of what CallInfo would look like in this temp file
+            let child = if ps1_file {
+                Command::new("pwsh")
+                    .args(&[
+                        "-NoLogo",
+                        "-NoProfile",
+                        "-ExecutionPolicy",
+                        "Bypass",
+                        "-File",
+                        &real_path.to_string_lossy(),
+                        &tmpfile
+                            .path()
+                            .to_str()
+                            .expect("Failed getting tmpfile path"),
+                    ])
+                    .spawn()
+            } else {
+                Command::new(path).arg(&tmpfile.path()).spawn()
+            };
+
+            if let Ok(mut child) = child {
+                let _ = child.wait();
+
+                Ok(OutputStream::empty())
+            } else {
+                Err(ShellError::untagged_runtime_error(
+                    "Could not create process for sink command",
+                ))
+            }
+        } else {
+            Err(ShellError::untagged_runtime_error(
+                "Could not open file to send sink command message",
+            ))
+        }
+    } else {
+        Err(ShellError::untagged_runtime_error(
+            "Could not create message to sink command",
+        ))
+    }
+}

crates/nu-cli/src/commands/clear.rs

@@ -6,35 +6,40 @@ use std::process::Command;
 
 pub struct Clear;
 
+#[async_trait]
 impl WholeStreamCommand for Clear {
     fn name(&self) -> &str {
         "clear"
     }
+
     fn signature(&self) -> Signature {
         Signature::build("clear")
     }
+
     fn usage(&self) -> &str {
-        "clears the terminal"
+        "Clears the terminal"
     }
-    fn run(
-        &self,
-        args: CommandArgs,
-        registry: &CommandRegistry,
-    ) -> Result<OutputStream, ShellError> {
-        clear(args, registry)
+
+    async fn run(&self, _: CommandArgs, _: &CommandRegistry) -> Result<OutputStream, ShellError> {
+        if cfg!(windows) {
+            Command::new("cmd")
+                .args(&["/C", "cls"])
+                .status()
+                .expect("failed to execute process");
+        } else if cfg!(unix) {
+            Command::new("/bin/sh")
+                .args(&["-c", "clear"])
+                .status()
+                .expect("failed to execute process");
+        }
+        Ok(OutputStream::empty())
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Clear the screen",
+            example: "clear",
+            result: None,
+        }]
     }
 }
-fn clear(_args: CommandArgs, _registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
-    if cfg!(windows) {
-        Command::new("cmd")
-            .args(&["/C", "cls"])
-            .status()
-            .expect("failed to execute process");
-    } else if cfg!(unix) {
-        Command::new("/bin/sh")
-            .args(&["-c", "clear"])
-            .status()
-            .expect("failed to execute process");
-    }
-    Ok(OutputStream::empty())
-}

crates/nu-cli/src/commands/clip.rs

@@ -1,106 +1,115 @@
-#[cfg(feature = "clipboard")]
-pub mod clipboard {
-    use crate::commands::WholeStreamCommand;
-    use crate::context::CommandRegistry;
-    use crate::prelude::*;
-    use futures::stream::StreamExt;
-    use nu_errors::ShellError;
-    use nu_protocol::{ReturnValue, Signature, Value};
+use crate::command_registry::CommandRegistry;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use futures::stream::StreamExt;
+use nu_errors::ShellError;
+use nu_protocol::{Signature, Value};
 
-    use clipboard::{ClipboardContext, ClipboardProvider};
+use clipboard::{ClipboardContext, ClipboardProvider};
 
-    pub struct Clip;
+pub struct Clip;
 
-    #[derive(Deserialize)]
-    pub struct ClipArgs {}
-
-    impl WholeStreamCommand for Clip {
-        fn name(&self) -> &str {
-            "clip"
-        }
-
-        fn signature(&self) -> Signature {
-            Signature::build("clip")
-        }
-
-        fn usage(&self) -> &str {
-            "Copy the contents of the pipeline to the copy/paste buffer"
-        }
-
-        fn run(
-            &self,
-            args: CommandArgs,
-            registry: &CommandRegistry,
-        ) -> Result<OutputStream, ShellError> {
-            args.process(registry, clip)?.run()
-        }
+#[async_trait]
+impl WholeStreamCommand for Clip {
+    fn name(&self) -> &str {
+        "clip"
     }
 
-    pub fn clip(
-        ClipArgs {}: ClipArgs,
-        RunnableContext { input, name, .. }: RunnableContext,
+    fn signature(&self) -> Signature {
+        Signature::build("clip")
+    }
+
+    fn usage(&self) -> &str {
+        "Copy the contents of the pipeline to the copy/paste buffer"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
-        let stream = async_stream! {
-            let values: Vec<Value> = input.collect().await;
-
-            let mut clip_stream = inner_clip(values, name).await;
-            while let Some(value) = clip_stream.next().await {
-                yield value;
-            }
-        };
-
-        let stream: BoxStream<'static, ReturnValue> = stream.boxed();
-
-        Ok(OutputStream::from(stream))
+        clip(args, registry).await
     }
 
-    async fn inner_clip(input: Vec<Value>, name: Tag) -> OutputStream {
-        if let Ok(clip_context) = ClipboardProvider::new() {
-            let mut clip_context: ClipboardContext = clip_context;
-            let mut new_copy_data = String::new();
-
-            if !input.is_empty() {
-                let mut first = true;
-                for i in input.iter() {
-                    if !first {
-                        new_copy_data.push_str("\n");
-                    } else {
-                        first = false;
-                    }
-
-                    let string: String = match i.as_string() {
-                        Ok(string) => string.to_string(),
-                        Err(_) => {
-                            return OutputStream::one(Err(ShellError::labeled_error(
-                                "Given non-string data",
-                                "expected strings from pipeline",
-                                name,
-                            )))
-                        }
-                    };
-
-                    new_copy_data.push_str(&string);
-                }
-            }
-
-            match clip_context.set_contents(new_copy_data) {
-                Ok(_) => {}
-                Err(_) => {
-                    return OutputStream::one(Err(ShellError::labeled_error(
-                        "Could not set contents of clipboard",
-                        "could not set contents of clipboard",
-                        name,
-                    )));
-                }
-            }
-
-            OutputStream::empty()
-        } else {
-            OutputStream::one(Err(ShellError::labeled_error(
-                "Could not open clipboard",
-                "could not open clipboard",
-                name,
-            )))
-        }
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Save text to the clipboard",
+                example: "echo 'secret value' | clip",
+                result: None,
+            },
+            Example {
+                description: "Save numbers to the clipboard",
+                example: "random integer 10000000..99999999 | clip",
+                result: None,
+            },
+        ]
+    }
+}
+
+pub async fn clip(
+    args: CommandArgs,
+    _registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let input = args.input;
+    let name = args.call_info.name_tag.clone();
+    let values: Vec<Value> = input.collect().await;
+
+    if let Ok(clip_context) = ClipboardProvider::new() {
+        let mut clip_context: ClipboardContext = clip_context;
+        let mut new_copy_data = String::new();
+
+        if !values.is_empty() {
+            let mut first = true;
+            for i in values.iter() {
+                if !first {
+                    new_copy_data.push('\n');
+                } else {
+                    first = false;
+                }
+
+                let string: String = i.convert_to_string();
+                if string.is_empty() {
+                    return Err(ShellError::labeled_error(
+                        "Unable to convert to string",
+                        "Unable to convert to string",
+                        name,
+                    ));
+                }
+
+                new_copy_data.push_str(&string);
+            }
+        }
+
+        match clip_context.set_contents(new_copy_data) {
+            Ok(_) => {}
+            Err(_) => {
+                return Err(ShellError::labeled_error(
+                    "Could not set contents of clipboard",
+                    "could not set contents of clipboard",
+                    name,
+                ));
+            }
+        }
+    } else {
+        return Err(ShellError::labeled_error(
+            "Could not open clipboard",
+            "could not open clipboard",
+            name,
+        ));
+    }
+    Ok(OutputStream::empty())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Clip;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Clip {})?)
     }
 }

crates/nu-cli/src/commands/command.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::help::get_help;
-use crate::context::CommandRegistry;
 use crate::deserializer::ConfigDeserializer;
 use crate::evaluate::evaluate_args::evaluate_args;
 use crate::prelude::*;
@@ -7,7 +7,8 @@ use derive_new::new;
 use getset::Getters;
 use nu_errors::ShellError;
 use nu_protocol::hir;
-use nu_protocol::{CallInfo, EvaluatedArgs, ReturnValue, Scope, Signature, Value};
+use nu_protocol::{CallInfo, EvaluatedArgs, ReturnSuccess, Scope, Signature, UntaggedValue, Value};
+use parking_lot::Mutex;
 use serde::{Deserialize, Serialize};
 use std::ops::Deref;
 use std::sync::atomic::AtomicBool;
@@ -16,27 +17,12 @@ use std::sync::atomic::AtomicBool;
 pub struct UnevaluatedCallInfo {
     pub args: hir::Call,
     pub name_tag: Tag,
-    pub scope: Scope,
+    pub scope: Arc<Scope>,
 }
 
 impl UnevaluatedCallInfo {
-    pub fn evaluate(self, registry: &CommandRegistry) -> Result<CallInfo, ShellError> {
-        let args = evaluate_args(&self.args, registry, &self.scope)?;
-
-        Ok(CallInfo {
-            args,
-            name_tag: self.name_tag,
-        })
-    }
-
-    pub fn evaluate_with_new_it(
-        self,
-        registry: &CommandRegistry,
-        it: &Value,
-    ) -> Result<CallInfo, ShellError> {
-        let mut scope = self.scope.clone();
-        scope = scope.set_it(it.clone());
-        let args = evaluate_args(&self.args, registry, &scope)?;
+    pub async fn evaluate(self, registry: &CommandRegistry) -> Result<CallInfo, ShellError> {
+        let args = evaluate_args(&self.args, registry, self.scope.clone()).await?;
 
         Ok(CallInfo {
             args,
@@ -49,44 +35,16 @@ impl UnevaluatedCallInfo {
     }
 }
 
-pub trait CallInfoExt {
-    fn process<'de, T: Deserialize<'de>>(
-        &self,
-        shell_manager: &ShellManager,
-        ctrl_c: Arc<AtomicBool>,
-        callback: fn(T, &RunnablePerItemContext) -> Result<OutputStream, ShellError>,
-    ) -> Result<RunnablePerItemArgs<T>, ShellError>;
-}
-
-impl CallInfoExt for CallInfo {
-    fn process<'de, T: Deserialize<'de>>(
-        &self,
-        shell_manager: &ShellManager,
-        ctrl_c: Arc<AtomicBool>,
-        callback: fn(T, &RunnablePerItemContext) -> Result<OutputStream, ShellError>,
-    ) -> Result<RunnablePerItemArgs<T>, ShellError> {
-        let mut deserializer = ConfigDeserializer::from_call_info(self.clone());
-
-        Ok(RunnablePerItemArgs {
-            args: T::deserialize(&mut deserializer)?,
-            context: RunnablePerItemContext {
-                shell_manager: shell_manager.clone(),
-                name: self.name_tag.clone(),
-                ctrl_c,
-            },
-            callback,
-        })
-    }
-}
-
 #[derive(Getters)]
 #[get = "pub(crate)"]
 pub struct CommandArgs {
     pub host: Arc<parking_lot::Mutex<Box<dyn Host>>>,
     pub ctrl_c: Arc<AtomicBool>,
+    pub current_errors: Arc<Mutex<Vec<ShellError>>>,
     pub shell_manager: ShellManager,
     pub call_info: UnevaluatedCallInfo,
     pub input: InputStream,
+    pub raw_input: String,
 }
 
 #[derive(Getters, Clone)]
@@ -94,6 +52,7 @@ pub struct CommandArgs {
 pub struct RawCommandArgs {
     pub host: Arc<parking_lot::Mutex<Box<dyn Host>>>,
     pub ctrl_c: Arc<AtomicBool>,
+    pub current_errors: Arc<Mutex<Vec<ShellError>>>,
     pub shell_manager: ShellManager,
     pub call_info: UnevaluatedCallInfo,
 }
@@ -103,9 +62,11 @@ impl RawCommandArgs {
         CommandArgs {
             host: self.host,
             ctrl_c: self.ctrl_c,
+            current_errors: self.current_errors,
             shell_manager: self.shell_manager,
             call_info: self.call_info,
             input: input.into(),
+            raw_input: String::default(),
         }
     }
 }
@@ -117,7 +78,7 @@ impl std::fmt::Debug for CommandArgs {
 }
 
 impl CommandArgs {
-    pub fn evaluate_once(
+    pub async fn evaluate_once(
         self,
         registry: &CommandRegistry,
     ) -> Result<EvaluatedWholeStreamCommandArgs, ShellError> {
@@ -125,7 +86,7 @@ impl CommandArgs {
         let ctrl_c = self.ctrl_c.clone();
         let shell_manager = self.shell_manager.clone();
         let input = self.input;
-        let call_info = self.call_info.evaluate(registry)?;
+        let call_info = self.call_info.evaluate(registry).await?;
 
         Ok(EvaluatedWholeStreamCommandArgs::new(
             host,
@@ -136,10 +97,10 @@ impl CommandArgs {
         ))
     }
 
-    pub fn evaluate_once_with_scope(
+    pub async fn evaluate_once_with_scope(
         self,
         registry: &CommandRegistry,
-        scope: &Scope,
+        scope: Arc<Scope>,
     ) -> Result<EvaluatedWholeStreamCommandArgs, ShellError> {
         let host = self.host.clone();
         let ctrl_c = self.ctrl_c.clone();
@@ -150,7 +111,7 @@ impl CommandArgs {
             args: self.call_info.args,
             scope: scope.clone(),
         };
-        let call_info = call_info.evaluate(registry)?;
+        let call_info = call_info.evaluate(registry).await?;
 
         Ok(EvaluatedWholeStreamCommandArgs::new(
             host,
@@ -161,133 +122,36 @@ impl CommandArgs {
         ))
     }
 
-    pub fn process<'de, T: Deserialize<'de>, O: ToOutputStream>(
+    pub async fn process<'de, T: Deserialize<'de>>(
         self,
         registry: &CommandRegistry,
-        callback: fn(T, RunnableContext) -> Result<O, ShellError>,
-    ) -> Result<RunnableArgs<T, O>, ShellError> {
-        let shell_manager = self.shell_manager.clone();
-        let host = self.host.clone();
-        let ctrl_c = self.ctrl_c.clone();
-        let args = self.evaluate_once(registry)?;
-        let call_info = args.call_info.clone();
-        let (input, args) = args.split();
-        let name_tag = args.call_info.name_tag;
-        let mut deserializer = ConfigDeserializer::from_call_info(call_info);
-
-        Ok(RunnableArgs {
-            args: T::deserialize(&mut deserializer)?,
-            context: RunnableContext {
-                input,
-                registry: registry.clone(),
-                shell_manager,
-                name: name_tag,
-                host,
-                ctrl_c,
-            },
-            callback,
-        })
-    }
-
-    pub fn process_raw<'de, T: Deserialize<'de>>(
-        self,
-        registry: &CommandRegistry,
-        callback: fn(T, RunnableContext, RawCommandArgs) -> Result<OutputStream, ShellError>,
-    ) -> Result<RunnableRawArgs<T>, ShellError> {
-        let raw_args = RawCommandArgs {
-            host: self.host.clone(),
-            ctrl_c: self.ctrl_c.clone(),
-            shell_manager: self.shell_manager.clone(),
-            call_info: self.call_info.clone(),
-        };
-
-        let shell_manager = self.shell_manager.clone();
-        let host = self.host.clone();
-        let ctrl_c = self.ctrl_c.clone();
-        let args = self.evaluate_once(registry)?;
+    ) -> Result<(T, InputStream), ShellError> {
+        let args = self.evaluate_once(registry).await?;
         let call_info = args.call_info.clone();
 
-        let (input, args) = args.split();
-        let name_tag = args.call_info.name_tag;
         let mut deserializer = ConfigDeserializer::from_call_info(call_info);
 
-        Ok(RunnableRawArgs {
-            args: T::deserialize(&mut deserializer)?,
-            context: RunnableContext {
-                input,
-                registry: registry.clone(),
-                shell_manager,
-                name: name_tag,
-                host,
-                ctrl_c,
-            },
-            raw_args,
-            callback,
-        })
+        Ok((T::deserialize(&mut deserializer)?, args.input))
     }
 }
 
-pub struct RunnablePerItemContext {
-    pub shell_manager: ShellManager,
-    pub name: Tag,
-    pub ctrl_c: Arc<AtomicBool>,
-}
-
 pub struct RunnableContext {
     pub input: InputStream,
     pub shell_manager: ShellManager,
     pub host: Arc<parking_lot::Mutex<Box<dyn Host>>>,
     pub ctrl_c: Arc<AtomicBool>,
+    pub current_errors: Arc<Mutex<Vec<ShellError>>>,
     pub registry: CommandRegistry,
     pub name: Tag,
+    pub raw_input: String,
 }
 
 impl RunnableContext {
-    pub fn get_command(&self, name: &str) -> Option<Arc<Command>> {
+    pub fn get_command(&self, name: &str) -> Option<Command> {
         self.registry.get_command(name)
     }
 }
 
-pub struct RunnablePerItemArgs<T> {
-    args: T,
-    context: RunnablePerItemContext,
-    callback: fn(T, &RunnablePerItemContext) -> Result<OutputStream, ShellError>,
-}
-
-impl<T> RunnablePerItemArgs<T> {
-    pub fn run(self) -> Result<OutputStream, ShellError> {
-        (self.callback)(self.args, &self.context)
-    }
-}
-
-pub struct RunnableArgs<T, O: ToOutputStream> {
-    args: T,
-    context: RunnableContext,
-    callback: fn(T, RunnableContext) -> Result<O, ShellError>,
-}
-
-impl<T, O: ToOutputStream> RunnableArgs<T, O> {
-    pub fn run(self) -> Result<OutputStream, ShellError> {
-        (self.callback)(self.args, self.context).map(|v| v.to_output_stream())
-    }
-}
-
-pub struct RunnableRawArgs<T> {
-    args: T,
-    raw_args: RawCommandArgs,
-    context: RunnableContext,
-    callback: fn(T, RunnableContext, RawCommandArgs) -> Result<OutputStream, ShellError>,
-}
-
-impl<T> RunnableRawArgs<T> {
-    pub fn run(self) -> OutputStream {
-        match (self.callback)(self.args, self.context, self.raw_args) {
-            Ok(stream) => stream,
-            Err(err) => OutputStream::one(Err(err)),
-        }
-    }
-}
-
 pub struct EvaluatedWholeStreamCommandArgs {
     pub args: EvaluatedCommandArgs,
     pub input: InputStream,
@@ -336,37 +200,6 @@ impl EvaluatedWholeStreamCommandArgs {
     }
 }
 
-#[derive(Getters)]
-#[get = "pub"]
-pub struct EvaluatedFilterCommandArgs {
-    args: EvaluatedCommandArgs,
-}
-
-impl Deref for EvaluatedFilterCommandArgs {
-    type Target = EvaluatedCommandArgs;
-    fn deref(&self) -> &Self::Target {
-        &self.args
-    }
-}
-
-impl EvaluatedFilterCommandArgs {
-    pub fn new(
-        host: Arc<parking_lot::Mutex<dyn Host>>,
-        ctrl_c: Arc<AtomicBool>,
-        shell_manager: ShellManager,
-        call_info: CallInfo,
-    ) -> EvaluatedFilterCommandArgs {
-        EvaluatedFilterCommandArgs {
-            args: EvaluatedCommandArgs {
-                host,
-                ctrl_c,
-                shell_manager,
-                call_info,
-            },
-        }
-    }
-}
-
 #[derive(Getters, new)]
 #[get = "pub(crate)"]
 pub struct EvaluatedCommandArgs {
@@ -383,10 +216,10 @@ impl EvaluatedCommandArgs {
 
     /// Get the nth positional argument, error if not possible
     pub fn expect_nth(&self, pos: usize) -> Result<&Value, ShellError> {
-        match self.call_info.args.nth(pos) {
-            None => Err(ShellError::unimplemented("Better error: expect_nth")),
-            Some(item) => Ok(item),
-        }
+        self.call_info
+            .args
+            .nth(pos)
+            .ok_or_else(|| ShellError::unimplemented("Better error: expect_nth"))
     }
 
     pub fn get(&self, name: &str) -> Option<&Value> {
@@ -398,6 +231,13 @@ impl EvaluatedCommandArgs {
     }
 }
 
+pub struct Example {
+    pub example: &'static str,
+    pub description: &'static str,
+    pub result: Option<Vec<Value>>,
+}
+
+#[async_trait]
 pub trait WholeStreamCommand: Send + Sync {
     fn name(&self) -> &str;
 
@@ -407,7 +247,7 @@ pub trait WholeStreamCommand: Send + Sync {
 
     fn usage(&self) -> &str;
 
-    fn run(
+    async fn run(
         &self,
         args: CommandArgs,
         registry: &CommandRegistry,
@@ -416,217 +256,85 @@ pub trait WholeStreamCommand: Send + Sync {
     fn is_binary(&self) -> bool {
         false
     }
-}
 
-pub trait PerItemCommand: Send + Sync {
-    fn name(&self) -> &str;
-
-    fn signature(&self) -> Signature {
-        Signature::new(self.name()).desc(self.usage()).filter()
-    }
-
-    fn usage(&self) -> &str;
-
-    fn run(
-        &self,
-        call_info: &CallInfo,
-        registry: &CommandRegistry,
-        raw_args: &RawCommandArgs,
-        input: Value,
-    ) -> Result<OutputStream, ShellError>;
-
-    fn is_binary(&self) -> bool {
+    // Commands that are not meant to be run by users
+    fn is_internal(&self) -> bool {
         false
     }
+
+    fn examples(&self) -> Vec<Example> {
+        Vec::new()
+    }
 }
 
-pub enum Command {
-    WholeStream(Arc<dyn WholeStreamCommand>),
-    PerItem(Arc<dyn PerItemCommand>),
-}
+#[derive(Clone)]
+pub struct Command(Arc<dyn WholeStreamCommand>);
 
 impl PrettyDebugWithSource for Command {
     fn pretty_debug(&self, source: &str) -> DebugDocBuilder {
-        match self {
-            Command::WholeStream(command) => b::typed(
-                "whole stream command",
-                b::description(command.name())
-                    + b::space()
-                    + b::equals()
-                    + b::space()
-                    + command.signature().pretty_debug(source),
-            ),
-            Command::PerItem(command) => b::typed(
-                "per item command",
-                b::description(command.name())
-                    + b::space()
-                    + b::equals()
-                    + b::space()
-                    + command.signature().pretty_debug(source),
-            ),
-        }
+        b::typed(
+            "whole stream command",
+            b::description(self.name())
+                + b::space()
+                + b::equals()
+                + b::space()
+                + self.signature().pretty_debug(source),
+        )
     }
 }
 
 impl std::fmt::Debug for Command {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            Command::WholeStream(command) => write!(f, "WholeStream({})", command.name()),
-            Command::PerItem(command) => write!(f, "PerItem({})", command.name()),
-        }
+        write!(f, "Command({})", self.name())
     }
 }
 
 impl Command {
     pub fn name(&self) -> &str {
-        match self {
-            Command::WholeStream(command) => command.name(),
-            Command::PerItem(command) => command.name(),
-        }
+        self.0.name()
     }
 
     pub fn signature(&self) -> Signature {
-        match self {
-            Command::WholeStream(command) => command.signature(),
-            Command::PerItem(command) => command.signature(),
-        }
+        self.0.signature()
     }
 
     pub fn usage(&self) -> &str {
-        match self {
-            Command::WholeStream(command) => command.usage(),
-            Command::PerItem(command) => command.usage(),
-        }
+        self.0.usage()
     }
 
-    pub fn run(&self, args: CommandArgs, registry: &CommandRegistry) -> OutputStream {
-        if args.call_info.switch_present("help") {
-            get_help(self.name(), self.usage(), self.signature()).into()
-        } else {
-            match self {
-                Command::WholeStream(command) => match command.run(args, registry) {
-                    Ok(stream) => stream,
-                    Err(err) => OutputStream::one(Err(err)),
-                },
-                Command::PerItem(command) => {
-                    self.run_helper(command.clone(), args, registry.clone())
-                }
-            }
-        }
+    pub fn examples(&self) -> Vec<Example> {
+        self.0.examples()
     }
 
-    fn run_helper(
-        &self,
-        command: Arc<dyn PerItemCommand>,
-        args: CommandArgs,
-        registry: CommandRegistry,
-    ) -> OutputStream {
-        let raw_args = RawCommandArgs {
-            host: args.host,
-            ctrl_c: args.ctrl_c,
-            shell_manager: args.shell_manager,
-            call_info: args.call_info,
-        };
-
-        let out = args
-            .input
-            .map(move |x| {
-                let call_info = UnevaluatedCallInfo {
-                    args: raw_args.call_info.args.clone(),
-                    name_tag: raw_args.call_info.name_tag.clone(),
-                    scope: raw_args.call_info.scope.clone().set_it(x.clone()),
-                }
-                .evaluate(&registry);
-                // let call_info = raw_args
-                //     .clone()
-                //     .call_info
-                //     .evaluate(&registry, &Scope::it_value(x.clone()));
-
-                match call_info {
-                    Ok(call_info) => match command.run(&call_info, &registry, &raw_args, x) {
-                        Ok(o) => o,
-                        Err(e) => {
-                            futures::stream::iter(vec![ReturnValue::Err(e)]).to_output_stream()
-                        }
-                    },
-                    Err(e) => futures::stream::iter(vec![ReturnValue::Err(e)]).to_output_stream(),
-                }
-            })
-            .flatten();
-
-        out.to_output_stream()
-    }
-
-    pub fn is_binary(&self) -> bool {
-        match self {
-            Command::WholeStream(command) => command.is_binary(),
-            Command::PerItem(command) => command.is_binary(),
-        }
-    }
-}
-
-pub struct FnFilterCommand {
-    name: String,
-    func: fn(EvaluatedFilterCommandArgs) -> Result<OutputStream, ShellError>,
-}
-
-impl WholeStreamCommand for FnFilterCommand {
-    fn name(&self) -> &str {
-        &self.name
-    }
-
-    fn usage(&self) -> &str {
-        "usage"
-    }
-
-    fn run(
+    pub async fn run(
         &self,
         args: CommandArgs,
         registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
-        let CommandArgs {
-            host,
-            ctrl_c,
-            shell_manager,
-            call_info,
-            input,
-        } = args;
-
-        let host: Arc<parking_lot::Mutex<dyn Host>> = host.clone();
-        let registry: CommandRegistry = registry.clone();
-        let func = self.func;
-
-        let result = input.map(move |it| {
+        if args.call_info.switch_present("help") {
+            let cl = self.0.clone();
             let registry = registry.clone();
-            let call_info = match call_info.clone().evaluate_with_new_it(&registry, &it) {
-                Err(err) => return OutputStream::from(vec![Err(err)]).values,
-                Ok(args) => args,
-            };
+            Ok(OutputStream::one(Ok(ReturnSuccess::Value(
+                UntaggedValue::string(get_help(&*cl, &registry)).into_value(Tag::unknown()),
+            ))))
+        } else {
+            self.0.run(args, registry).await
+        }
+    }
 
-            let args = EvaluatedFilterCommandArgs::new(
-                host.clone(),
-                ctrl_c.clone(),
-                shell_manager.clone(),
-                call_info,
-            );
+    pub fn is_binary(&self) -> bool {
+        self.0.is_binary()
+    }
 
-            match func(args) {
-                Err(err) => OutputStream::from(vec![Err(err)]).values,
-                Ok(stream) => stream.values,
-            }
-        });
+    pub fn is_internal(&self) -> bool {
+        self.0.is_internal()
+    }
 
-        let result = result.flatten();
-        let result: BoxStream<ReturnValue> = result.boxed();
-
-        Ok(result.into())
+    pub fn stream_command(&self) -> &dyn WholeStreamCommand {
+        &*self.0
     }
 }
 
-pub fn whole_stream_command(command: impl WholeStreamCommand + 'static) -> Arc<Command> {
-    Arc::new(Command::WholeStream(Arc::new(command)))
-}
-
-pub fn per_item_command(command: impl PerItemCommand + 'static) -> Arc<Command> {
-    Arc::new(Command::PerItem(Arc::new(command)))
+pub fn whole_stream_command(command: impl WholeStreamCommand + 'static) -> Command {
+    Command(Arc::new(command))
 }

crates/nu-cli/src/commands/compact.rs

@@ -1,9 +1,10 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
+use futures::future;
 use futures::stream::StreamExt;
 use nu_errors::ShellError;
-use nu_protocol::{Signature, SyntaxShape, UntaggedValue, Value};
+use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
 use nu_source::Tagged;
 
 pub struct Compact;
@@ -13,6 +14,7 @@ pub struct CompactArgs {
     rest: Vec<Tagged<String>>,
 }
 
+#[async_trait]
 impl WholeStreamCommand for Compact {
     fn name(&self) -> &str {
         "compact"
@@ -26,36 +28,68 @@ impl WholeStreamCommand for Compact {
         "Creates a table with non-empty rows"
     }
 
-    fn run(
+    async fn run(
         &self,
         args: CommandArgs,
         registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
-        args.process(registry, compact)?.run()
+        compact(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Filter out all directory entries having no 'target'",
+            example: "ls -la | compact target",
+            result: None,
+        }]
     }
 }
 
-pub fn compact(
-    CompactArgs { rest: columns }: CompactArgs,
-    RunnableContext { input, .. }: RunnableContext,
+pub async fn compact(
+    args: CommandArgs,
+    registry: &CommandRegistry,
 ) -> Result<OutputStream, ShellError> {
-    let objects = input.filter(move |item| {
-        let keep = if columns.is_empty() {
-            item.is_some()
-        } else {
-            match item {
-                Value {
-                    value: UntaggedValue::Row(ref r),
-                    ..
-                } => columns
-                    .iter()
-                    .all(|field| r.get_data(field).borrow().is_some()),
-                _ => false,
-            }
-        };
-
-        futures::future::ready(keep)
-    });
-
-    Ok(objects.from_input_stream())
+    let registry = registry.clone();
+    let (CompactArgs { rest: columns }, input) = args.process(&registry).await?;
+    Ok(input
+        .filter_map(move |item| {
+            future::ready(if columns.is_empty() {
+                if !item.is_empty() {
+                    Some(ReturnSuccess::value(item))
+                } else {
+                    None
+                }
+            } else {
+                match item {
+                    Value {
+                        value: UntaggedValue::Row(ref r),
+                        ..
+                    } => {
+                        if columns
+                            .iter()
+                            .all(|field| r.get_data(field).borrow().is_some())
+                        {
+                            Some(ReturnSuccess::value(item))
+                        } else {
+                            None
+                        }
+                    }
+                    _ => None,
+                }
+            })
+        })
+        .to_output_stream())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Compact;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Compact {})?)
+    }
 }

crates/nu-cli/src/commands/config.rs

@@ -1,188 +0,0 @@
-use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
-use crate::data::config;
-use crate::prelude::*;
-use nu_errors::ShellError;
-use nu_protocol::{Primitive, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
-use nu_source::Tagged;
-use std::path::PathBuf;
-
-pub struct Config;
-
-#[derive(Deserialize)]
-pub struct ConfigArgs {
-    load: Option<Tagged<PathBuf>>,
-    set: Option<(Tagged<String>, Value)>,
-    set_into: Option<Tagged<String>>,
-    get: Option<Tagged<String>>,
-    clear: Tagged<bool>,
-    remove: Option<Tagged<String>>,
-    path: Tagged<bool>,
-}
-
-impl WholeStreamCommand for Config {
-    fn name(&self) -> &str {
-        "config"
-    }
-
-    fn signature(&self) -> Signature {
-        Signature::build("config")
-            .named(
-                "load",
-                SyntaxShape::Path,
-                "load the config from the path give",
-                Some('l'),
-            )
-            .named(
-                "set",
-                SyntaxShape::Any,
-                "set a value in the config, eg) --set [key value]",
-                Some('s'),
-            )
-            .named(
-                "set_into",
-                SyntaxShape::String,
-                "sets a variable from values in the pipeline",
-                Some('i'),
-            )
-            .named(
-                "get",
-                SyntaxShape::Any,
-                "get a value from the config",
-                Some('g'),
-            )
-            .named(
-                "remove",
-                SyntaxShape::Any,
-                "remove a value from the config",
-                Some('r'),
-            )
-            .switch("clear", "clear the config", Some('c'))
-            .switch("path", "return the path to the config file", Some('p'))
-    }
-
-    fn usage(&self) -> &str {
-        "Configuration management."
-    }
-
-    fn run(
-        &self,
-        args: CommandArgs,
-        registry: &CommandRegistry,
-    ) -> Result<OutputStream, ShellError> {
-        args.process(registry, config)?.run()
-    }
-}
-
-pub fn config(
-    ConfigArgs {
-        load,
-        set,
-        set_into,
-        get,
-        clear,
-        remove,
-        path,
-    }: ConfigArgs,
-    RunnableContext { name, input, .. }: RunnableContext,
-) -> Result<OutputStream, ShellError> {
-    let name_span = name.clone();
-
-    let stream = async_stream! {
-        let configuration = if let Some(supplied) = load {
-            Some(supplied.item().clone())
-        } else {
-            None
-        };
-
-        let mut result = crate::data::config::read(name_span, &configuration)?;
-
-        if let Some(v) = get {
-            let key = v.to_string();
-            let value = result
-                .get(&key)
-                .ok_or_else(|| ShellError::labeled_error("Missing key in config", "key", v.tag()))?;
-
-            match value {
-                Value {
-                    value: UntaggedValue::Table(list),
-                    ..
-                } => {
-                    for l in list {
-                        let value = l.clone();
-                        yield ReturnSuccess::value(l.clone());
-                    }
-                }
-                x => yield ReturnSuccess::value(x.clone()),
-            }
-        }
-        else if let Some((key, value)) = set {
-            result.insert(key.to_string(), value.clone());
-
-            config::write(&result, &configuration)?;
-
-            yield ReturnSuccess::value(UntaggedValue::Row(result.into()).into_value(&value.tag));
-        }
-        else if let Some(v) = set_into {
-            let rows: Vec<Value> = input.collect().await;
-            let key = v.to_string();
-
-            if rows.len() == 0 {
-                yield Err(ShellError::labeled_error("No values given for set_into", "needs value(s) from pipeline", v.tag()));
-            } else if rows.len() == 1 {
-                // A single value
-                let value = &rows[0];
-
-                result.insert(key.to_string(), value.clone());
-
-                config::write(&result, &configuration)?;
-
-                yield ReturnSuccess::value(UntaggedValue::Row(result.into()).into_value(name));
-            } else {
-                // Take in the pipeline as a table
-                let value = UntaggedValue::Table(rows).into_value(name.clone());
-
-                result.insert(key.to_string(), value.clone());
-
-                config::write(&result, &configuration)?;
-
-                yield ReturnSuccess::value(UntaggedValue::Row(result.into()).into_value(name));
-            }
-        }
-        else if let Tagged { item: true, tag } = clear {
-            result.clear();
-
-            config::write(&result, &configuration)?;
-
-            yield ReturnSuccess::value(UntaggedValue::Row(result.into()).into_value(tag));
-
-            return;
-        }
-        else if let Tagged { item: true, tag } = path {
-            let path = config::default_path_for(&configuration)?;
-
-            yield ReturnSuccess::value(UntaggedValue::Primitive(Primitive::Path(path)).into_value(tag));
-        }
-        else if let Some(v) = remove {
-            let key = v.to_string();
-
-            if result.contains_key(&key) {
-                result.swap_remove(&key);
-                config::write(&result, &configuration)?
-            } else {
-                yield Err(ShellError::labeled_error(
-                    "Key does not exist in config",
-                    "key",
-                    v.tag(),
-                ));
-            }
-
-            yield ReturnSuccess::value(UntaggedValue::Row(result.into()).into_value(v.tag()));
-        }
-        else {
-            yield ReturnSuccess::value(UntaggedValue::Row(result.into()).into_value(name));
-        }
-    };
-
-    Ok(stream.to_output_stream())
-}

crates/nu-cli/src/commands/config/clear.rs

@@ -0,0 +1,57 @@
+use crate::command_registry::CommandRegistry;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{ReturnSuccess, Signature, UntaggedValue};
+
+pub struct SubCommand;
+
+#[async_trait]
+impl WholeStreamCommand for SubCommand {
+    fn name(&self) -> &str {
+        "config clear"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("config clear")
+    }
+
+    fn usage(&self) -> &str {
+        "clear the config"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        clear(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Clear the config (be careful!)",
+            example: "config clear",
+            result: None,
+        }]
+    }
+}
+
+pub async fn clear(
+    args: CommandArgs,
+    _registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let name_span = args.call_info.name_tag.clone();
+
+    // NOTE: None because we are not loading a new config file, we just want to read from the
+    // existing config
+    let mut result = nu_data::config::read(name_span, &None)?;
+
+    result.clear();
+
+    config::write(&result, &None)?;
+
+    Ok(OutputStream::one(ReturnSuccess::value(
+        UntaggedValue::Row(result.into()).into_value(args.call_info.name_tag),
+    )))
+}

crates/nu-cli/src/commands/config/command.rs

@@ -0,0 +1,37 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use crate::{CommandArgs, CommandRegistry, OutputStream};
+use nu_errors::ShellError;
+use nu_protocol::{ReturnSuccess, Signature, UntaggedValue};
+
+pub struct Command;
+
+#[async_trait]
+impl WholeStreamCommand for Command {
+    fn name(&self) -> &str {
+        "config"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("config")
+    }
+
+    fn usage(&self) -> &str {
+        "Configuration management."
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        _registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        let name_span = args.call_info.name_tag.clone();
+        let name = args.call_info.name_tag;
+        let result = nu_data::config::read(name_span, &None)?;
+
+        Ok(futures::stream::iter(vec![ReturnSuccess::value(
+            UntaggedValue::Row(result.into()).into_value(name),
+        )])
+        .to_output_stream())
+    }
+}

crates/nu-cli/src/commands/config/get.rs

@@ -0,0 +1,76 @@
+use crate::command_registry::CommandRegistry;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{ColumnPath, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
+
+pub struct SubCommand;
+
+#[derive(Deserialize)]
+pub struct GetArgs {
+    path: ColumnPath,
+}
+
+#[async_trait]
+impl WholeStreamCommand for SubCommand {
+    fn name(&self) -> &str {
+        "config get"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("config get").required(
+            "get",
+            SyntaxShape::ColumnPath,
+            "value to get from the config",
+        )
+    }
+
+    fn usage(&self) -> &str {
+        "Gets a value from the config"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        get(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Get the current startup commands",
+            example: "config get startup",
+            result: None,
+        }]
+    }
+}
+
+pub async fn get(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let name_tag = args.call_info.name_tag.clone();
+    let (GetArgs { path }, _) = args.process(&registry).await?;
+
+    // NOTE: None because we are not loading a new config file, we just want to read from the
+    // existing config
+    let result = UntaggedValue::row(nu_data::config::read(&name_tag, &None)?).into_value(&name_tag);
+
+    let value = crate::commands::get::get_column_path(&path, &result)?;
+
+    Ok(match value {
+        Value {
+            value: UntaggedValue::Table(list),
+            ..
+        } => {
+            let list: Vec<_> = list
+                .iter()
+                .map(|x| ReturnSuccess::value(x.clone()))
+                .collect();
+
+            futures::stream::iter(list).to_output_stream()
+        }
+        x => OutputStream::one(ReturnSuccess::value(x)),
+    })
+}

crates/nu-cli/src/commands/config/load.rs

@@ -0,0 +1,59 @@
+use crate::command_registry::CommandRegistry;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue};
+use nu_source::Tagged;
+use std::path::PathBuf;
+
+pub struct SubCommand;
+
+#[derive(Deserialize)]
+pub struct LoadArgs {
+    load: Tagged<PathBuf>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for SubCommand {
+    fn name(&self) -> &str {
+        "config load"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("config load").required(
+            "load",
+            SyntaxShape::Path,
+            "Path to load the config from",
+        )
+    }
+
+    fn usage(&self) -> &str {
+        "Loads the config from the path given"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        set(args, registry).await
+    }
+}
+
+pub async fn set(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let name = args.call_info.name_tag.clone();
+    let name_span = args.call_info.name_tag.clone();
+    let (LoadArgs { load }, _) = args.process(&registry).await?;
+
+    let configuration = load.item().clone();
+
+    let result = nu_data::config::read(name_span, &Some(configuration))?;
+
+    Ok(futures::stream::iter(vec![ReturnSuccess::value(
+        UntaggedValue::Row(result.into()).into_value(name),
+    )])
+    .to_output_stream())
+}

crates/nu-cli/src/commands/config/mod.rs

@@ -0,0 +1,17 @@
+pub mod clear;
+pub mod command;
+pub mod get;
+pub mod load;
+pub mod path;
+pub mod remove;
+pub mod set;
+pub mod set_into;
+
+pub use clear::SubCommand as ConfigClear;
+pub use command::Command as Config;
+pub use get::SubCommand as ConfigGet;
+pub use load::SubCommand as ConfigLoad;
+pub use path::SubCommand as ConfigPath;
+pub use remove::SubCommand as ConfigRemove;
+pub use set::SubCommand as ConfigSet;
+pub use set_into::SubCommand as ConfigSetInto;

crates/nu-cli/src/commands/config/path.rs

@@ -0,0 +1,49 @@
+use crate::command_registry::CommandRegistry;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{Primitive, ReturnSuccess, Signature, UntaggedValue};
+
+pub struct SubCommand;
+
+#[async_trait]
+impl WholeStreamCommand for SubCommand {
+    fn name(&self) -> &str {
+        "config path"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("config path")
+    }
+
+    fn usage(&self) -> &str {
+        "return the path to the config file"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        path(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Get the path to the current config file",
+            example: "config path",
+            result: None,
+        }]
+    }
+}
+
+pub async fn path(
+    args: CommandArgs,
+    _registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let path = config::default_path()?;
+
+    Ok(OutputStream::one(ReturnSuccess::value(
+        UntaggedValue::Primitive(Primitive::Path(path)).into_value(args.call_info.name_tag),
+    )))
+}

crates/nu-cli/src/commands/config/remove.rs

@@ -0,0 +1,75 @@
+use crate::command_registry::CommandRegistry;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue};
+use nu_source::Tagged;
+
+pub struct SubCommand;
+
+#[derive(Deserialize)]
+pub struct RemoveArgs {
+    remove: Tagged<String>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for SubCommand {
+    fn name(&self) -> &str {
+        "config remove"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("config remove").required(
+            "remove",
+            SyntaxShape::Any,
+            "remove a value from the config",
+        )
+    }
+
+    fn usage(&self) -> &str {
+        "Removes a value from the config"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        remove(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Remove the startup commands",
+            example: "config remove startup",
+            result: None,
+        }]
+    }
+}
+
+pub async fn remove(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let name_span = args.call_info.name_tag.clone();
+    let (RemoveArgs { remove }, _) = args.process(&registry).await?;
+
+    let mut result = nu_data::config::read(name_span, &None)?;
+
+    let key = remove.to_string();
+
+    if result.contains_key(&key) {
+        result.swap_remove(&key);
+        config::write(&result, &None)?;
+        Ok(futures::stream::iter(vec![ReturnSuccess::value(
+            UntaggedValue::Row(result.into()).into_value(remove.tag()),
+        )])
+        .to_output_stream())
+    } else {
+        Err(ShellError::labeled_error(
+            "Key does not exist in config",
+            "key",
+            remove.tag(),
+        ))
+    }
+}

crates/nu-cli/src/commands/config/set.rs

@@ -0,0 +1,97 @@
+use crate::command_registry::CommandRegistry;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{ColumnPath, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
+
+pub struct SubCommand;
+
+#[derive(Deserialize)]
+pub struct SetArgs {
+    path: ColumnPath,
+    value: Value,
+}
+
+#[async_trait]
+impl WholeStreamCommand for SubCommand {
+    fn name(&self) -> &str {
+        "config set"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("config set")
+            .required("key", SyntaxShape::ColumnPath, "variable name to set")
+            .required("value", SyntaxShape::Any, "value to use")
+    }
+
+    fn usage(&self) -> &str {
+        "Sets a value in the config"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        set(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Set auto pivoting",
+                example: "config set pivot_mode always",
+                result: None,
+            },
+            Example {
+                description: "Set line editor options",
+                example: "config set line_editor [[edit_mode, completion_type]; [emacs circular]]",
+                result: None,
+            },
+            Example {
+                description: "Set coloring options",
+                example: "config set color_config [[header_align header_bold]; [left $true]]",
+                result: None,
+            },
+            Example {
+                description: "Set nested options",
+                example: "config set color_config.header_color white",
+                result: None,
+            },
+        ]
+    }
+}
+
+pub async fn set(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let name_tag = args.call_info.name_tag.clone();
+    let (SetArgs { path, mut value }, _) = args.process(&registry).await?;
+
+    // NOTE: None because we are not loading a new config file, we just want to read from the
+    // existing config
+    let raw_entries = nu_data::config::read(&name_tag, &None)?;
+    let configuration = UntaggedValue::row(raw_entries).into_value(&name_tag);
+
+    if let UntaggedValue::Table(rows) = &value.value {
+        if rows.len() == 1 && rows[0].is_row() {
+            value = rows[0].clone();
+        }
+    }
+
+    match configuration.forgiving_insert_data_at_column_path(&path, value) {
+        Ok(Value {
+            value: UntaggedValue::Row(changes),
+            ..
+        }) => {
+            config::write(&changes.entries, &None)?;
+
+            Ok(OutputStream::one(ReturnSuccess::value(
+                UntaggedValue::Row(changes).into_value(name_tag),
+            )))
+        }
+        Ok(_) => Ok(OutputStream::empty()),
+        Err(reason) => Err(reason),
+    }
+}

crates/nu-cli/src/commands/config/set_into.rs

@@ -0,0 +1,98 @@
+use crate::command_registry::CommandRegistry;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
+use nu_source::Tagged;
+
+pub struct SubCommand;
+
+#[derive(Deserialize)]
+pub struct SetIntoArgs {
+    set_into: Tagged<String>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for SubCommand {
+    fn name(&self) -> &str {
+        "config set_into"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("config set_into").required(
+            "set_into",
+            SyntaxShape::String,
+            "sets a variable from values in the pipeline",
+        )
+    }
+
+    fn usage(&self) -> &str {
+        "Sets a value in the config"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        set_into(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Store the contents of the pipeline as a path",
+            example: "echo ['/usr/bin' '/bin'] | config set_into path",
+            result: None,
+        }]
+    }
+}
+
+pub async fn set_into(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let name_span = args.call_info.name_tag.clone();
+    let name = args.call_info.name_tag.clone();
+
+    let (SetIntoArgs { set_into: v }, input) = args.process(&registry).await?;
+
+    // NOTE: None because we are not loading a new config file, we just want to read from the
+    // existing config
+    let mut result = nu_data::config::read(name_span, &None)?;
+
+    // In the original code, this is set to `Some` if the `load flag is set`
+    let configuration = None;
+
+    let rows: Vec<Value> = input.collect().await;
+    let key = v.to_string();
+
+    Ok(if rows.is_empty() {
+        return Err(ShellError::labeled_error(
+            "No values given for set_into",
+            "needs value(s) from pipeline",
+            v.tag(),
+        ));
+    } else if rows.len() == 1 {
+        // A single value
+        let value = &rows[0];
+
+        result.insert(key, value.clone());
+
+        config::write(&result, &configuration)?;
+
+        OutputStream::one(ReturnSuccess::value(
+            UntaggedValue::Row(result.into()).into_value(name),
+        ))
+    } else {
+        // Take in the pipeline as a table
+        let value = UntaggedValue::Table(rows).into_value(name.clone());
+
+        result.insert(key, value);
+
+        config::write(&result, &configuration)?;
+
+        OutputStream::one(ReturnSuccess::value(
+            UntaggedValue::Row(result.into()).into_value(name),
+        ))
+    })
+}

crates/nu-cli/src/commands/constants.rs

@@ -0,0 +1,358 @@
+pub const BAT_LANGUAGES: &[&str] = &[
+    "as",
+    "csv",
+    "tsv",
+    "applescript",
+    "script editor",
+    "s",
+    "S",
+    "adoc",
+    "asciidoc",
+    "asc",
+    "asa",
+    "yasm",
+    "nasm",
+    "asm",
+    "inc",
+    "mac",
+    "awk",
+    "bat",
+    "cmd",
+    "bib",
+    "sh",
+    "bash",
+    "zsh",
+    ".bash_aliases",
+    ".bash_completions",
+    ".bash_functions",
+    ".bash_login",
+    ".bash_logout",
+    ".bash_profile",
+    ".bash_variables",
+    ".bashrc",
+    ".profile",
+    ".textmate_init",
+    ".zshrc",
+    "PKGBUILD",
+    ".ebuild",
+    ".eclass",
+    "c",
+    "h",
+    "cs",
+    "csx",
+    "cpp",
+    "cc",
+    "cp",
+    "cxx",
+    "c++",
+    "C",
+    "h",
+    "hh",
+    "hpp",
+    "hxx",
+    "h++",
+    "inl",
+    "ipp",
+    "cabal",
+    "clj",
+    "cljc",
+    "cljs",
+    "edn",
+    "CMakeLists.txt",
+    "cmake",
+    "h.in",
+    "hh.in",
+    "hpp.in",
+    "hxx.in",
+    "h++.in",
+    "CMakeCache.txt",
+    "cr",
+    "css",
+    "css.erb",
+    "css.liquid",
+    "d",
+    "di",
+    "dart",
+    "diff",
+    "patch",
+    "Dockerfile",
+    "dockerfile",
+    "ex",
+    "exs",
+    "elm",
+    "erl",
+    "hrl",
+    "Emakefile",
+    "emakefile",
+    "fs",
+    "fsi",
+    "fsx",
+    "fs",
+    "fsi",
+    "fsx",
+    "fish",
+    "attributes",
+    "gitattributes",
+    ".gitattributes",
+    "COMMIT_EDITMSG",
+    "MERGE_MSG",
+    "TAG_EDITMSG",
+    "gitconfig",
+    ".gitconfig",
+    ".gitmodules",
+    "exclude",
+    "gitignore",
+    ".gitignore",
+    ".git",
+    "gitlog",
+    "git-rebase-todo",
+    "go",
+    "dot",
+    "DOT",
+    "gv",
+    "groovy",
+    "gvy",
+    "gradle",
+    "Jenkinsfile",
+    "hs",
+    "hs",
+    "hsc",
+    "show-nonprintable",
+    "html",
+    "htm",
+    "shtml",
+    "xhtml",
+    "asp",
+    "html.eex",
+    "yaws",
+    "rails",
+    "rhtml",
+    "erb",
+    "html.erb",
+    "adp",
+    "twig",
+    "html.twig",
+    "ini",
+    "INI",
+    "INF",
+    "reg",
+    "REG",
+    "lng",
+    "cfg",
+    "CFG",
+    "desktop",
+    "url",
+    "URL",
+    ".editorconfig",
+    ".hgrc",
+    "hgrc",
+    "java",
+    "bsh",
+    "properties",
+    "jsp",
+    "js",
+    "htc",
+    "js",
+    "jsx",
+    "babel",
+    "es6",
+    "js.erb",
+    "json",
+    "sublime-settings",
+    "sublime-menu",
+    "sublime-keymap",
+    "sublime-mousemap",
+    "sublime-theme",
+    "sublime-build",
+    "sublime-project",
+    "sublime-completions",
+    "sublime-commands",
+    "sublime-macro",
+    "sublime-color-scheme",
+    "ipynb",
+    "Pipfile.lock",
+    "jsonnet",
+    "libsonnet",
+    "libjsonnet",
+    "jl",
+    "kt",
+    "kts",
+    "tex",
+    "ltx",
+    "less",
+    "css.less",
+    "lisp",
+    "cl",
+    "clisp",
+    "l",
+    "mud",
+    "el",
+    "scm",
+    "ss",
+    "lsp",
+    "fasl",
+    "lhs",
+    "lua",
+    "make",
+    "GNUmakefile",
+    "makefile",
+    "Makefile",
+    "makefile.am",
+    "Makefile.am",
+    "makefile.in",
+    "Makefile.in",
+    "OCamlMakefile",
+    "mak",
+    "mk",
+    "md",
+    "mdown",
+    "markdown",
+    "markdn",
+    "matlab",
+    "build",
+    "nix",
+    "m",
+    "h",
+    "mm",
+    "M",
+    "h",
+    "ml",
+    "mli",
+    "mll",
+    "mly",
+    "pas",
+    "p",
+    "dpr",
+    "pl",
+    "pm",
+    "pod",
+    "t",
+    "PL",
+    "php",
+    "php3",
+    "php4",
+    "php5",
+    "php7",
+    "phps",
+    "phpt",
+    "phtml",
+    "txt",
+    "ps1",
+    "psm1",
+    "psd1",
+    "proto",
+    "protodevel",
+    "pb.txt",
+    "proto.text",
+    "textpb",
+    "pbtxt",
+    "prototxt",
+    "pp",
+    "epp",
+    "purs",
+    "py",
+    "py3",
+    "pyw",
+    "pyi",
+    "pyx",
+    "pyx.in",
+    "pxd",
+    "pxd.in",
+    "pxi",
+    "pxi.in",
+    "rpy",
+    "cpy",
+    "SConstruct",
+    "Sconstruct",
+    "sconstruct",
+    "SConscript",
+    "gyp",
+    "gypi",
+    "Snakefile",
+    "wscript",
+    "R",
+    "r",
+    "s",
+    "S",
+    "Rprofile",
+    "rd",
+    "re",
+    "rst",
+    "rest",
+    "robot",
+    "rb",
+    "Appfile",
+    "Appraisals",
+    "Berksfile",
+    "Brewfile",
+    "capfile",
+    "cgi",
+    "Cheffile",
+    "config.ru",
+    "Deliverfile",
+    "Fastfile",
+    "fcgi",
+    "Gemfile",
+    "gemspec",
+    "Guardfile",
+    "irbrc",
+    "jbuilder",
+    "Podfile",
+    "podspec",
+    "prawn",
+    "rabl",
+    "rake",
+    "Rakefile",
+    "Rantfile",
+    "rbx",
+    "rjs",
+    "ruby.rail",
+    "Scanfile",
+    "simplecov",
+    "Snapfile",
+    "thor",
+    "Thorfile",
+    "Vagrantfile",
+    "haml",
+    "sass",
+    "rxml",
+    "builder",
+    "rs",
+    "scala",
+    "sbt",
+    "sql",
+    "ddl",
+    "dml",
+    "erbsql",
+    "sql.erb",
+    "swift",
+    "log",
+    "tcl",
+    "tf",
+    "tfvars",
+    "hcl",
+    "sty",
+    "cls",
+    "textile",
+    "toml",
+    "tml",
+    "Cargo.lock",
+    "Gopkg.lock",
+    "Pipfile",
+    "ts",
+    "tsx",
+    "varlink",
+    "vim",
+    ".vimrc",
+    "xml",
+    "xsd",
+    "xslt",
+    "tld",
+    "dtml",
+    "rss",
+    "opml",
+    "svg",
+    "yaml",
+    "yml",
+    "sublime-syntax",
+];

crates/nu-cli/src/commands/count.rs

@@ -1,46 +1,91 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use futures::stream::StreamExt;
 use nu_errors::ShellError;
-use nu_protocol::{ReturnSuccess, Signature, UntaggedValue, Value};
+use nu_protocol::{Signature, UntaggedValue, Value};
 
 pub struct Count;
 
 #[derive(Deserialize)]
-pub struct CountArgs {}
+pub struct CountArgs {
+    column: bool,
+}
 
+#[async_trait]
 impl WholeStreamCommand for Count {
     fn name(&self) -> &str {
         "count"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("count")
+        Signature::build("count").switch(
+            "column",
+            "Calculate number of columns in table",
+            Some('c'),
+        )
     }
 
     fn usage(&self) -> &str {
-        "Show the total number of rows."
+        "Show the total number of rows or items."
     }
 
-    fn run(
+    async fn run(
         &self,
         args: CommandArgs,
         registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
-        args.process(registry, count)?.run()
+        let tag = args.call_info.name_tag.clone();
+        let (CountArgs { column }, input) = args.process(&registry).await?;
+        let rows: Vec<Value> = input.collect().await;
+
+        let count = if column {
+            if rows.is_empty() {
+                0
+            } else {
+                match &rows[0].value {
+                    UntaggedValue::Row(dictionary) => dictionary.length(),
+                    _ => {
+                        return Err(ShellError::labeled_error(
+                            "Cannot obtain column count",
+                            "cannot obtain column count",
+                            tag,
+                        ));
+                    }
+                }
+            }
+        } else {
+            rows.len()
+        };
+
+        Ok(OutputStream::one(UntaggedValue::int(count).into_value(tag)))
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Count the number of entries in a list",
+                example: "echo [1 2 3 4 5] | count",
+                result: Some(vec![UntaggedValue::int(5).into()]),
+            },
+            Example {
+                description: "Count the number of columns in the calendar table",
+                example: "cal | count -c",
+                result: None,
+            },
+        ]
     }
 }
 
-pub fn count(
-    CountArgs {}: CountArgs,
-    RunnableContext { input, name, .. }: RunnableContext,
-) -> Result<OutputStream, ShellError> {
-    let stream = async_stream! {
-        let rows: Vec<Value> = input.collect().await;
+#[cfg(test)]
+mod tests {
+    use super::Count;
+    use super::ShellError;
 
-        yield ReturnSuccess::value(UntaggedValue::int(rows.len()).into_value(name))
-    };
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
 
-    Ok(stream.to_output_stream())
+        Ok(test_examples(Count {})?)
+    }
 }

crates/nu-cli/src/commands/cp.rs

@@ -1,8 +1,8 @@
-use crate::commands::command::RunnablePerItemContext;
-use crate::context::CommandRegistry;
+use crate::command_registry::CommandRegistry;
+use crate::commands::WholeStreamCommand;
 use crate::prelude::*;
 use nu_errors::ShellError;
-use nu_protocol::{CallInfo, Signature, SyntaxShape, Value};
+use nu_protocol::{Signature, SyntaxShape};
 use nu_source::Tagged;
 use std::path::PathBuf;
 
@@ -15,7 +15,8 @@ pub struct CopyArgs {
     pub recursive: Tagged<bool>,
 }
 
-impl PerItemCommand for Cpy {
+#[async_trait]
+impl WholeStreamCommand for Cpy {
     fn name(&self) -> &str {
         "cp"
     }
@@ -35,20 +36,42 @@ impl PerItemCommand for Cpy {
         "Copy files."
     }
 
-    fn run(
+    async fn run(
         &self,
-        call_info: &CallInfo,
-        _registry: &CommandRegistry,
-        raw_args: &RawCommandArgs,
-        _input: Value,
+        args: CommandArgs,
+        registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
-        call_info
-            .process(&raw_args.shell_manager, raw_args.ctrl_c.clone(), cp)?
-            .run()
+        let shell_manager = args.shell_manager.clone();
+        let name = args.call_info.name_tag.clone();
+        let (args, _) = args.process(&registry).await?;
+        shell_manager.cp(args, name)
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Copy myfile to dir_b",
+                example: "cp myfile dir_b",
+                result: None,
+            },
+            Example {
+                description: "Recursively copy dir_a to dir_b",
+                example: "cp -r dir_a dir_b",
+                result: None,
+            },
+        ]
     }
 }
 
-fn cp(args: CopyArgs, context: &RunnablePerItemContext) -> Result<OutputStream, ShellError> {
-    let shell_manager = context.shell_manager.clone();
-    shell_manager.cp(args, context)
+#[cfg(test)]
+mod tests {
+    use super::Cpy;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Cpy {})?)
+    }
 }

crates/nu-cli/src/commands/date.rs

@@ -1,95 +0,0 @@
-use crate::prelude::*;
-use chrono::{DateTime, Local, Utc};
-use nu_errors::ShellError;
-use nu_protocol::{Dictionary, Value};
-
-use crate::commands::WholeStreamCommand;
-use chrono::{Datelike, TimeZone, Timelike};
-use core::fmt::Display;
-use indexmap::IndexMap;
-use nu_protocol::{Signature, UntaggedValue};
-
-pub struct Date;
-
-impl WholeStreamCommand for Date {
-    fn name(&self) -> &str {
-        "date"
-    }
-
-    fn signature(&self) -> Signature {
-        Signature::build("date")
-            .switch("utc", "use universal time (UTC)", Some('u'))
-            .switch("local", "use the local time", Some('l'))
-    }
-
-    fn usage(&self) -> &str {
-        "Get the current datetime."
-    }
-
-    fn run(
-        &self,
-        args: CommandArgs,
-        registry: &CommandRegistry,
-    ) -> Result<OutputStream, ShellError> {
-        date(args, registry)
-    }
-}
-
-pub fn date_to_value<T: TimeZone>(dt: DateTime<T>, tag: Tag) -> Value
-where
-    T::Offset: Display,
-{
-    let mut indexmap = IndexMap::new();
-
-    indexmap.insert(
-        "year".to_string(),
-        UntaggedValue::int(dt.year()).into_value(&tag),
-    );
-    indexmap.insert(
-        "month".to_string(),
-        UntaggedValue::int(dt.month()).into_value(&tag),
-    );
-    indexmap.insert(
-        "day".to_string(),
-        UntaggedValue::int(dt.day()).into_value(&tag),
-    );
-    indexmap.insert(
-        "hour".to_string(),
-        UntaggedValue::int(dt.hour()).into_value(&tag),
-    );
-    indexmap.insert(
-        "minute".to_string(),
-        UntaggedValue::int(dt.minute()).into_value(&tag),
-    );
-    indexmap.insert(
-        "second".to_string(),
-        UntaggedValue::int(dt.second()).into_value(&tag),
-    );
-
-    let tz = dt.offset();
-    indexmap.insert(
-        "timezone".to_string(),
-        UntaggedValue::string(format!("{}", tz)).into_value(&tag),
-    );
-
-    UntaggedValue::Row(Dictionary::from(indexmap)).into_value(&tag)
-}
-
-pub fn date(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once(registry)?;
-
-    let mut date_out = VecDeque::new();
-    let tag = args.call_info.name_tag.clone();
-
-    let value = if args.has("utc") {
-        let utc: DateTime<Utc> = Utc::now();
-        date_to_value(utc, tag)
-    } else {
-        let local: DateTime<Local> = Local::now();
-        date_to_value(local, tag)
-    };
-
-    date_out.push_back(value);
-
-    Ok(futures::stream::iter(date_out).to_output_stream())
-}

crates/nu-cli/src/commands/date/command.rs

@@ -0,0 +1,47 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{ReturnSuccess, Signature, UntaggedValue};
+
+pub struct Command;
+
+#[async_trait]
+impl WholeStreamCommand for Command {
+    fn name(&self) -> &str {
+        "date"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("date")
+    }
+
+    fn usage(&self) -> &str {
+        "Apply date function"
+    }
+
+    async fn run(
+        &self,
+        _args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        let registry = registry.clone();
+
+        Ok(OutputStream::one(ReturnSuccess::value(
+            UntaggedValue::string(crate::commands::help::get_help(&Command, &registry))
+                .into_value(Tag::unknown()),
+        )))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Command;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Command {})?)
+    }
+}

crates/nu-cli/src/commands/date/format.rs

@@ -0,0 +1,117 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{
+    Dictionary, Primitive, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value,
+};
+use nu_source::Tagged;
+use std::fmt::{self, write};
+
+pub struct Date;
+
+#[derive(Deserialize)]
+pub struct FormatArgs {
+    format: Tagged<String>,
+    table: bool,
+}
+
+#[async_trait]
+impl WholeStreamCommand for Date {
+    fn name(&self) -> &str {
+        "date format"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("date format")
+            .required("format", SyntaxShape::String, "strftime format")
+            .switch("table", "print date in a table", Some('t'))
+    }
+
+    fn usage(&self) -> &str {
+        "Format a given date using the given format string."
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        format(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Format the current date",
+                example: "date now | date format '%Y.%m.%d_%H %M %S,%z'",
+                result: None,
+            },
+            Example {
+                description: "Format the current date and print in a table",
+                example: "date now | date format -t '%Y-%m-%d_%H:%M:%S %z'",
+                result: None,
+            },
+        ]
+    }
+}
+
+pub async fn format(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+    let tag = args.call_info.name_tag.clone();
+    let (FormatArgs { format, table }, input) = args.process(&registry).await?;
+
+    Ok(input
+        .map(move |value| match value {
+            Value {
+                value: UntaggedValue::Primitive(Primitive::Date(dt)),
+                ..
+            } => {
+                let mut output = String::new();
+                if let Err(fmt::Error) =
+                    write(&mut output, format_args!("{}", dt.format(&format.item)))
+                {
+                    Err(ShellError::labeled_error(
+                        "The date format is invalid",
+                        "invalid strftime format",
+                        &format.tag,
+                    ))
+                } else {
+                    let value = if table {
+                        let mut indexmap = IndexMap::new();
+                        indexmap.insert(
+                            "formatted".to_string(),
+                            UntaggedValue::string(&output).into_value(&tag),
+                        );
+
+                        UntaggedValue::Row(Dictionary::from(indexmap)).into_value(&tag)
+                    } else {
+                        UntaggedValue::string(&output).into_value(&tag)
+                    };
+
+                    ReturnSuccess::value(value)
+                }
+            }
+            _ => Err(ShellError::labeled_error(
+                "Expected a date from pipeline",
+                "requires date input",
+                &tag,
+            )),
+        })
+        .to_output_stream())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Date;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Date {})?)
+    }
+}

crates/nu-cli/src/commands/date/list_timezone.rs

@@ -0,0 +1,82 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use chrono_tz::TZ_VARIANTS;
+use indexmap::IndexMap;
+use nu_errors::ShellError;
+use nu_protocol::{Dictionary, ReturnSuccess, Signature, UntaggedValue};
+
+pub struct Date;
+
+#[async_trait]
+impl WholeStreamCommand for Date {
+    fn name(&self) -> &str {
+        "date list-timezone"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("date list-timezone")
+    }
+
+    fn usage(&self) -> &str {
+        "List supported time zones."
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        list_timezone(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "List all supported time zones",
+                example: "date list-timezone",
+                result: None,
+            },
+            Example {
+                description: "List all supported European time zones",
+                example: "date list-timezone | where timezone =~ Europe",
+                result: None,
+            },
+        ]
+    }
+}
+
+async fn list_timezone(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let args = args.evaluate_once(&registry).await?;
+    let tag = args.call_info.name_tag.clone();
+
+    let list = TZ_VARIANTS.iter().map(move |tz| {
+        let mut entries = IndexMap::new();
+
+        entries.insert(
+            "timezone".to_string(),
+            UntaggedValue::string(tz.name()).into_value(&tag),
+        );
+
+        Ok(ReturnSuccess::Value(
+            UntaggedValue::Row(Dictionary { entries }).into_value(&tag),
+        ))
+    });
+
+    Ok(futures::stream::iter(list).to_output_stream())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Date;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Date {})?)
+    }
+}

crates/nu-cli/src/commands/date/mod.rs

@@ -0,0 +1,15 @@
+pub mod command;
+pub mod format;
+pub mod list_timezone;
+pub mod now;
+pub mod to_table;
+pub mod to_timezone;
+
+mod parser;
+
+pub use command::Command as Date;
+pub use format::Date as DateFormat;
+pub use list_timezone::Date as DateListTimeZone;
+pub use now::Date as DateNow;
+pub use to_table::Date as DateToTable;
+pub use to_timezone::Date as DateToTimeZone;

crates/nu-cli/src/commands/date/now.rs

@@ -0,0 +1,57 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use chrono::{DateTime, Local};
+use nu_errors::ShellError;
+use nu_protocol::{Signature, UntaggedValue};
+
+pub struct Date;
+
+#[async_trait]
+impl WholeStreamCommand for Date {
+    fn name(&self) -> &str {
+        "date now"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("date now")
+    }
+
+    fn usage(&self) -> &str {
+        "Get the current date."
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        now(args, registry).await
+    }
+}
+
+pub async fn now(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let args = args.evaluate_once(&registry).await?;
+    let tag = args.call_info.name_tag.clone();
+
+    let now: DateTime<Local> = Local::now();
+
+    let value = UntaggedValue::date(now.with_timezone(now.offset())).into_value(&tag);
+
+    Ok(OutputStream::one(value))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Date;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Date {})?)
+    }
+}

crates/nu-cli/src/commands/date/parser.rs

@@ -0,0 +1,107 @@
+// Modified from chrono::format::scan
+
+use chrono::{DateTime, FixedOffset, Local, Offset, TimeZone};
+use chrono_tz::Tz;
+use titlecase::titlecase;
+
+#[derive(Debug, Clone, PartialEq, Eq, Copy)]
+pub enum ParseErrorKind {
+    /// Given field is out of permitted range.
+    OutOfRange,
+
+    /// The input string has some invalid character sequence for given formatting items.
+    Invalid,
+
+    /// The input string has been prematurely ended.
+    TooShort,
+}
+
+pub fn datetime_in_timezone(
+    dt: &DateTime<FixedOffset>,
+    s: &str,
+) -> Result<DateTime<FixedOffset>, ParseErrorKind> {
+    match timezone_offset_internal(s, true, true) {
+        Ok(offset) => match FixedOffset::east_opt(offset) {
+            Some(offset) => Ok(dt.with_timezone(&offset)),
+            None => Err(ParseErrorKind::OutOfRange),
+        },
+        Err(ParseErrorKind::Invalid) => {
+            if s.to_lowercase() == "local" {
+                Ok(dt.with_timezone(Local::now().offset()))
+            } else {
+                let tz: Tz = parse_timezone_internal(s)?;
+                let offset = tz.offset_from_utc_datetime(&dt.naive_utc()).fix();
+                Ok(dt.with_timezone(&offset))
+            }
+        }
+        Err(e) => Err(e),
+    }
+}
+
+fn parse_timezone_internal(s: &str) -> Result<Tz, ParseErrorKind> {
+    if let Ok(tz) = s.parse() {
+        Ok(tz)
+    } else if let Ok(tz) = titlecase(s).parse() {
+        Ok(tz)
+    } else if let Ok(tz) = s.to_uppercase().parse() {
+        Ok(tz)
+    } else {
+        Err(ParseErrorKind::Invalid)
+    }
+}
+
+fn timezone_offset_internal(
+    mut s: &str,
+    consume_colon: bool,
+    allow_missing_minutes: bool,
+) -> Result<i32, ParseErrorKind> {
+    fn digits(s: &str) -> Result<(u8, u8), ParseErrorKind> {
+        let b = s.as_bytes();
+        if b.len() < 2 {
+            Err(ParseErrorKind::TooShort)
+        } else {
+            Ok((b[0], b[1]))
+        }
+    }
+    let negative = match s.as_bytes().first() {
+        Some(&b'+') => false,
+        Some(&b'-') => true,
+        Some(_) => return Err(ParseErrorKind::Invalid),
+        None => return Err(ParseErrorKind::TooShort),
+    };
+    s = &s[1..];
+
+    // hours (00--99)
+    let hours = match digits(s)? {
+        (h1 @ b'0'..=b'9', h2 @ b'0'..=b'9') => i32::from((h1 - b'0') * 10 + (h2 - b'0')),
+        _ => return Err(ParseErrorKind::Invalid),
+    };
+    s = &s[2..];
+
+    // colons (and possibly other separators)
+    if consume_colon {
+        s = s.trim_start_matches(|c: char| c == ':' || c.is_whitespace());
+    }
+
+    // minutes (00--59)
+    // if the next two items are digits then we have to add minutes
+    let minutes = if let Ok(ds) = digits(s) {
+        match ds {
+            (m1 @ b'0'..=b'5', m2 @ b'0'..=b'9') => i32::from((m1 - b'0') * 10 + (m2 - b'0')),
+            (b'6'..=b'9', b'0'..=b'9') => return Err(ParseErrorKind::OutOfRange),
+            _ => return Err(ParseErrorKind::Invalid),
+        }
+    } else if allow_missing_minutes {
+        0
+    } else {
+        return Err(ParseErrorKind::TooShort);
+    };
+    match s.len() {
+        len if len >= 2 => &s[2..],
+        len if len == 0 => s,
+        _ => return Err(ParseErrorKind::TooShort),
+    };
+
+    let seconds = hours * 3600 + minutes * 60;
+    Ok(if negative { -seconds } else { seconds })
+}

crates/nu-cli/src/commands/date/to_table.rs

@@ -0,0 +1,113 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use chrono::{Datelike, Timelike};
+use indexmap::IndexMap;
+use nu_errors::ShellError;
+use nu_protocol::{Dictionary, Primitive, ReturnSuccess, Signature, UntaggedValue, Value};
+
+pub struct Date;
+
+#[async_trait]
+impl WholeStreamCommand for Date {
+    fn name(&self) -> &str {
+        "date to-table"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("date to-table")
+    }
+
+    fn usage(&self) -> &str {
+        "Print the date in a structured table."
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        to_table(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Print the current date in a table",
+            example: "date now | date to-table",
+            result: None,
+        }]
+    }
+}
+
+async fn to_table(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+    let args = args.evaluate_once(&registry).await?;
+    let tag = args.call_info.name_tag.clone();
+    let input = args.input;
+
+    Ok(input
+        .map(move |value| match value {
+            Value {
+                value: UntaggedValue::Primitive(Primitive::Date(dt)),
+                ..
+            } => {
+                let mut indexmap = IndexMap::new();
+
+                indexmap.insert(
+                    "year".to_string(),
+                    UntaggedValue::int(dt.year()).into_value(&tag),
+                );
+                indexmap.insert(
+                    "month".to_string(),
+                    UntaggedValue::int(dt.month()).into_value(&tag),
+                );
+                indexmap.insert(
+                    "day".to_string(),
+                    UntaggedValue::int(dt.day()).into_value(&tag),
+                );
+                indexmap.insert(
+                    "hour".to_string(),
+                    UntaggedValue::int(dt.hour()).into_value(&tag),
+                );
+                indexmap.insert(
+                    "minute".to_string(),
+                    UntaggedValue::int(dt.minute()).into_value(&tag),
+                );
+                indexmap.insert(
+                    "second".to_string(),
+                    UntaggedValue::int(dt.second()).into_value(&tag),
+                );
+
+                let tz = dt.offset();
+                indexmap.insert(
+                    "timezone".to_string(),
+                    UntaggedValue::string(format!("{}", tz)).into_value(&tag),
+                );
+
+                let value = UntaggedValue::Row(Dictionary::from(indexmap)).into_value(&tag);
+
+                ReturnSuccess::value(value)
+            }
+            _ => Err(ShellError::labeled_error(
+                "Expected a date from pipeline",
+                "requires date input",
+                &tag,
+            )),
+        })
+        .to_output_stream())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Date;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Date {})?)
+    }
+}

crates/nu-cli/src/commands/date/to_timezone.rs

@@ -0,0 +1,118 @@
+use crate::commands::date::parser::{datetime_in_timezone, ParseErrorKind};
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{Primitive, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
+use nu_source::Tagged;
+
+pub struct Date;
+
+#[derive(Deserialize)]
+struct DateToTimeZoneArgs {
+    timezone: Tagged<String>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for Date {
+    fn name(&self) -> &str {
+        "date to-timezone"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("date to-timezone").required(
+            "time zone",
+            SyntaxShape::String,
+            "time zone description",
+        )
+    }
+
+    fn usage(&self) -> &str {
+        "Convert a date to a given time zone.
+        
+Use `date list-timezone` to list all supported time zones.
+        "
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        to_timezone(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Get the current date in UTC+05:00",
+                example: "date now | date to-timezone +0500",
+                result: None,
+            },
+            Example {
+                description: "Get the current local date",
+                example: "date now | date to-timezone local",
+                result: None,
+            },
+            Example {
+                description: "Get the current date in Hawaii",
+                example: "date now | date to-timezone US/Hawaii",
+                result: None,
+            },
+        ]
+    }
+}
+
+async fn to_timezone(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+    let tag = args.call_info.name_tag.clone();
+    let (DateToTimeZoneArgs { timezone }, input) = args.process(&registry).await?;
+
+    Ok(input
+        .map(move |value| match value {
+            Value {
+                value: UntaggedValue::Primitive(Primitive::Date(dt)),
+                ..
+            } => match datetime_in_timezone(&dt, &timezone.item) {
+                Ok(dt) => {
+                    let value = UntaggedValue::date(dt).into_value(&tag);
+
+                    ReturnSuccess::value(value)
+                }
+                Err(e) => Err(ShellError::labeled_error(
+                    error_message(e),
+                    "invalid time zone",
+                    &timezone.tag,
+                )),
+            },
+            _ => Err(ShellError::labeled_error(
+                "Expected a date from pipeline",
+                "requires date input",
+                &tag,
+            )),
+        })
+        .to_output_stream())
+}
+
+fn error_message(err: ParseErrorKind) -> &'static str {
+    match err {
+        ParseErrorKind::Invalid => "The time zone description is invalid",
+        ParseErrorKind::OutOfRange => "The time zone offset is out of range",
+        ParseErrorKind::TooShort => "The format of the time zone is invalid",
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Date;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Date {})?)
+    }
+}

crates/nu-cli/src/commands/debug.rs

@@ -10,6 +10,7 @@ pub struct DebugArgs {
     raw: bool,
 }
 
+#[async_trait]
 impl WholeStreamCommand for Debug {
     fn name(&self) -> &str {
         "debug"
@@ -23,19 +24,21 @@ impl WholeStreamCommand for Debug {
         "Print the Rust debug representation of the values"
     }
 
-    fn run(
+    async fn run(
         &self,
         args: CommandArgs,
         registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
-        args.process(registry, debug_value)?.run()
+        debug_value(args, registry).await
     }
 }
 
-fn debug_value(
-    DebugArgs { raw }: DebugArgs,
-    RunnableContext { input, .. }: RunnableContext,
-) -> Result<impl ToOutputStream, ShellError> {
+async fn debug_value(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+    let (DebugArgs { raw }, input) = args.process(&registry).await?;
     Ok(input
         .map(move |v| {
             if raw {
@@ -48,3 +51,16 @@ fn debug_value(
         })
         .to_output_stream())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::Debug;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Debug {})?)
+    }
+}

crates/nu-cli/src/commands/default.rs

@@ -1,5 +1,5 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
@@ -14,6 +14,7 @@ struct DefaultArgs {
 
 pub struct Default;
 
+#[async_trait]
 impl WholeStreamCommand for Default {
     fn name(&self) -> &str {
         "default"
@@ -33,43 +34,61 @@ impl WholeStreamCommand for Default {
         "Sets a default row's column if missing."
     }
 
-    fn run(
+    async fn run(
         &self,
         args: CommandArgs,
         registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
-        args.process(registry, default)?.run()
+        default(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Give a default 'target' to all file entries",
+            example: "ls -la | default target 'nothing'",
+            result: None,
+        }]
     }
 }
 
-fn default(
-    DefaultArgs { column, value }: DefaultArgs,
-    RunnableContext { input, .. }: RunnableContext,
+async fn default(
+    args: CommandArgs,
+    registry: &CommandRegistry,
 ) -> Result<OutputStream, ShellError> {
-    let stream = input
-        .map(move |item| {
-            let mut result = VecDeque::new();
+    let registry = registry.clone();
+    let (DefaultArgs { column, value }, input) = args.process(&registry).await?;
 
-            let should_add = match item {
+    Ok(input
+        .map(move |item| {
+            let should_add = matches!(
+                item,
                 Value {
                     value: UntaggedValue::Row(ref r),
                     ..
-                } => r.get_data(&column.item).borrow().is_none(),
-                _ => false,
-            };
+                } if r.get_data(&column.item).borrow().is_none()
+            );
 
             if should_add {
                 match item.insert_data_at_path(&column.item, value.clone()) {
-                    Some(new_value) => result.push_back(ReturnSuccess::value(new_value)),
-                    None => result.push_back(ReturnSuccess::value(item)),
+                    Some(new_value) => ReturnSuccess::value(new_value),
+                    None => ReturnSuccess::value(item),
                 }
             } else {
-                result.push_back(ReturnSuccess::value(item));
+                ReturnSuccess::value(item)
             }
-
-            futures::stream::iter(result)
         })
-        .flatten();
-
-    Ok(stream.to_output_stream())
+        .to_output_stream())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Default;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Default {})?)
+    }
 }

crates/nu-cli/src/commands/describe.rs

@@ -0,0 +1,61 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+
+use nu_errors::ShellError;
+use nu_protocol::{ReturnSuccess, Signature, UntaggedValue};
+
+pub struct Describe;
+
+#[derive(Deserialize)]
+pub struct DescribeArgs {}
+
+#[async_trait]
+impl WholeStreamCommand for Describe {
+    fn name(&self) -> &str {
+        "describe"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("describe")
+    }
+
+    fn usage(&self) -> &str {
+        "Describes the objects in the stream."
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        describe(args, registry).await
+    }
+}
+
+pub async fn describe(
+    args: CommandArgs,
+    _registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    Ok(args
+        .input
+        .map(|row| {
+            let name = value::format_type(&row, 100);
+            ReturnSuccess::value(
+                UntaggedValue::string(name).into_value(Tag::unknown_anchor(row.tag.span)),
+            )
+        })
+        .to_output_stream())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Describe;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Describe {})?)
+    }
+}

crates/nu-cli/src/commands/do_.rs

@@ -0,0 +1,128 @@
+use crate::commands::classified::block::run_block;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{
+    hir::Block, hir::ExternalRedirection, ReturnSuccess, Signature, SyntaxShape, Value,
+};
+
+pub struct Do;
+
+#[derive(Deserialize, Debug)]
+struct DoArgs {
+    block: Block,
+    ignore_errors: bool,
+}
+
+#[async_trait]
+impl WholeStreamCommand for Do {
+    fn name(&self) -> &str {
+        "do"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("do")
+            .required("block", SyntaxShape::Block, "the block to run ")
+            .switch(
+                "ignore_errors",
+                "ignore errors as the block runs",
+                Some('i'),
+            )
+    }
+
+    fn usage(&self) -> &str {
+        "Runs a block, optionally ignoring errors"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        do_(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Run the block",
+                example: r#"do { echo hello }"#,
+                result: Some(vec![Value::from("hello")]),
+            },
+            Example {
+                description: "Run the block and ignore errors",
+                example: r#"do -i { thisisnotarealcommand }"#,
+                result: Some(vec![Value::nothing()]),
+            },
+        ]
+    }
+}
+
+async fn do_(
+    raw_args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+    let external_redirection = raw_args.call_info.args.external_redirection;
+
+    let mut context = EvaluationContext::from_raw(&raw_args, &registry);
+    let scope = raw_args.call_info.scope.clone();
+    let (
+        DoArgs {
+            ignore_errors,
+            mut block,
+        },
+        input,
+    ) = raw_args.process(&registry).await?;
+
+    let block_redirection = match external_redirection {
+        ExternalRedirection::None => {
+            if ignore_errors {
+                ExternalRedirection::Stderr
+            } else {
+                ExternalRedirection::None
+            }
+        }
+        ExternalRedirection::Stdout => {
+            if ignore_errors {
+                ExternalRedirection::StdoutAndStderr
+            } else {
+                ExternalRedirection::Stdout
+            }
+        }
+        x => x,
+    };
+
+    block.set_redirect(block_redirection);
+
+    let result = run_block(&block, &mut context, input, scope).await;
+
+    if ignore_errors {
+        // To properly ignore errors we need to redirect stderr, consume it, and remove
+        // any errors we see in the process.
+
+        match result {
+            Ok(mut stream) => {
+                let output = stream.drain_vec().await;
+                context.clear_errors();
+                Ok(futures::stream::iter(output).to_output_stream())
+            }
+            Err(_) => Ok(OutputStream::one(ReturnSuccess::value(Value::nothing()))),
+        }
+    } else {
+        result.map(|x| x.to_output_stream())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Do;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Do {})?)
+    }
+}

crates/nu-cli/src/commands/drop.rs

@@ -0,0 +1,96 @@
+use crate::command_registry::CommandRegistry;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{Signature, SyntaxShape, UntaggedValue};
+use nu_source::Tagged;
+
+pub struct Drop;
+
+#[derive(Deserialize)]
+pub struct DropArgs {
+    rows: Option<Tagged<u64>>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for Drop {
+    fn name(&self) -> &str {
+        "drop"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("drop").optional(
+            "rows",
+            SyntaxShape::Number,
+            "starting from the back, the number of rows to remove",
+        )
+    }
+
+    fn usage(&self) -> &str {
+        "Remove the last number of rows. If you want to remove columns, try 'reject'."
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        drop(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Remove the last item of a list/table",
+                example: "echo [1 2 3] | drop",
+                result: Some(vec![
+                    UntaggedValue::int(1).into(),
+                    UntaggedValue::int(2).into(),
+                ]),
+            },
+            Example {
+                description: "Remove the last 2 items of a list/table",
+                example: "echo [1 2 3] | drop 2",
+                result: Some(vec![UntaggedValue::int(1).into()]),
+            },
+        ]
+    }
+}
+
+async fn drop(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
+    let (DropArgs { rows }, input) = args.process(&registry).await?;
+    let v: Vec<_> = input.into_vec().await;
+
+    let rows_to_drop = if let Some(quantity) = rows {
+        *quantity as usize
+    } else {
+        1
+    };
+
+    Ok(if rows_to_drop == 0 {
+        futures::stream::iter(v).to_output_stream()
+    } else {
+        let k = if v.len() < rows_to_drop {
+            0
+        } else {
+            v.len() - rows_to_drop
+        };
+
+        let iter = v.into_iter().take(k);
+
+        futures::stream::iter(iter).to_output_stream()
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Drop;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Drop {})?)
+    }
+}

crates/nu-cli/src/commands/du.rs

@@ -1,14 +1,13 @@
-extern crate filesize;
-
-use crate::commands::command::RunnablePerItemContext;
+use crate::commands::WholeStreamCommand;
 use crate::prelude::*;
 use filesize::file_real_size_fast;
 use glob::*;
 use indexmap::map::IndexMap;
 use nu_errors::ShellError;
-use nu_protocol::{CallInfo, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
+use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
 use nu_source::Tagged;
 use std::path::PathBuf;
+use std::sync::atomic::Ordering;
 
 const NAME: &str = "du";
 const GLOB_PARAMS: MatchOptions = MatchOptions {
@@ -31,7 +30,8 @@ pub struct DuArgs {
     min_size: Option<Tagged<u64>>,
 }
 
-impl PerItemCommand for Du {
+#[async_trait]
+impl WholeStreamCommand for Du {
     fn name(&self) -> &str {
         NAME
     }
@@ -73,22 +73,30 @@ impl PerItemCommand for Du {
         "Find disk usage sizes of specified items"
     }
 
-    fn run(
+    async fn run(
         &self,
-        call_info: &CallInfo,
-        _registry: &CommandRegistry,
-        raw_args: &RawCommandArgs,
-        _input: Value,
+        args: CommandArgs,
+        registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
-        call_info
-            .process(&raw_args.shell_manager, raw_args.ctrl_c.clone(), du)?
-            .run()
+        du(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Disk usage of the current directory",
+            example: "du",
+            result: None,
+        }]
     }
 }
 
-fn du(args: DuArgs, ctx: &RunnablePerItemContext) -> Result<OutputStream, ShellError> {
-    let tag = ctx.name.clone();
+async fn du(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+    let tag = args.call_info.name_tag.clone();
+    let ctrl_c = args.ctrl_c.clone();
+    let ctrl_c_copy = ctrl_c.clone();
 
+    let (args, _): (DuArgs, _) = args.process(&registry).await?;
     let exclude = args.exclude.map_or(Ok(None), move |x| {
         Pattern::new(&x.item)
             .map(Option::Some)
@@ -117,7 +125,6 @@ fn du(args: DuArgs, ctx: &RunnablePerItemContext) -> Result<OutputStream, ShellE
     })
     .map(|v| v.map_err(glob_err_into));
 
-    let ctrl_c = ctx.ctrl_c.clone();
     let all = args.all;
     let deref = args.deref;
     let max_depth = args.max_depth.map(|f| f.item);
@@ -131,25 +138,30 @@ fn du(args: DuArgs, ctx: &RunnablePerItemContext) -> Result<OutputStream, ShellE
         all,
     };
 
-    let stream = futures::stream::iter(paths)
-        .interruptible(ctrl_c)
-        .map(move |path| match path {
-            Ok(p) => {
-                if p.is_dir() {
-                    Ok(ReturnSuccess::Value(
-                        DirInfo::new(p, &params, max_depth).into(),
-                    ))
-                } else {
-                    FileInfo::new(p, deref, tag.clone()).map(|v| ReturnSuccess::Value(v.into()))
-                }
-            }
-            Err(e) => Err(e),
-        });
+    let inp = futures::stream::iter(paths);
 
-    Ok(stream.to_output_stream())
+    Ok(inp
+        .flat_map(move |path| match path {
+            Ok(p) => {
+                let mut output = vec![];
+                if p.is_dir() {
+                    output.push(Ok(ReturnSuccess::Value(
+                        DirInfo::new(p, &params, max_depth, ctrl_c.clone()).into(),
+                    )));
+                } else {
+                    for v in FileInfo::new(p, deref, tag.clone()).into_iter() {
+                        output.push(Ok(ReturnSuccess::Value(v.into())));
+                    }
+                }
+                futures::stream::iter(output)
+            }
+            Err(e) => futures::stream::iter(vec![Err(e)]),
+        })
+        .interruptible(ctrl_c_copy)
+        .to_output_stream())
 }
 
-struct DirBuilder {
+pub struct DirBuilder {
     tag: Tag,
     min: Option<u64>,
     deref: bool,
@@ -157,7 +169,25 @@ struct DirBuilder {
     all: bool,
 }
 
-struct DirInfo {
+impl DirBuilder {
+    pub fn new(
+        tag: Tag,
+        min: Option<u64>,
+        deref: bool,
+        exclude: Option<Pattern>,
+        all: bool,
+    ) -> DirBuilder {
+        DirBuilder {
+            tag,
+            min,
+            deref,
+            exclude,
+            all,
+        }
+    }
+}
+
+pub struct DirInfo {
     dirs: Vec<DirInfo>,
     files: Vec<FileInfo>,
     errors: Vec<ShellError>,
@@ -200,7 +230,12 @@ impl FileInfo {
 }
 
 impl DirInfo {
-    fn new(path: impl Into<PathBuf>, params: &DirBuilder, depth: Option<u64>) -> Self {
+    pub fn new(
+        path: impl Into<PathBuf>,
+        params: &DirBuilder,
+        depth: Option<u64>,
+        ctrl_c: Arc<AtomicBool>,
+    ) -> Self {
         let path = path.into();
 
         let mut s = Self {
@@ -216,9 +251,15 @@ impl DirInfo {
         match std::fs::read_dir(&s.path) {
             Ok(d) => {
                 for f in d {
+                    if ctrl_c.load(Ordering::SeqCst) {
+                        break;
+                    }
+
                     match f {
                         Ok(i) => match i.file_type() {
-                            Ok(t) if t.is_dir() => s = s.add_dir(i.path(), depth, &params),
+                            Ok(t) if t.is_dir() => {
+                                s = s.add_dir(i.path(), depth, &params, ctrl_c.clone())
+                            }
                             Ok(_t) => s = s.add_file(i.path(), &params),
                             Err(e) => s = s.add_error(e.into()),
                         },
@@ -236,6 +277,7 @@ impl DirInfo {
         path: impl Into<PathBuf>,
         mut depth: Option<u64>,
         params: &DirBuilder,
+        ctrl_c: Arc<AtomicBool>,
     ) -> Self {
         if let Some(current) = depth {
             if let Some(new) = current.checked_sub(1) {
@@ -245,7 +287,7 @@ impl DirInfo {
             }
         }
 
-        let d = DirInfo::new(path, &params, depth);
+        let d = DirInfo::new(path, &params, depth, ctrl_c);
         self.size += d.size;
         self.blocks += d.blocks;
         self.dirs.push(d);
@@ -280,6 +322,10 @@ impl DirInfo {
         self.errors.push(e);
         self
     }
+
+    pub fn get_size(&self) -> u64 {
+        self.size
+    }
 }
 
 fn glob_err_into(e: GlobError) -> ShellError {
@@ -297,7 +343,7 @@ where
         let values = vec.into_iter().map(Into::into).collect::<Vec<Value>>();
         UntaggedValue::Table(values)
     }
-    .retag(tag)
+    .into_value(tag)
 }
 
 impl From<DirInfo> for Value {
@@ -306,17 +352,17 @@ impl From<DirInfo> for Value {
 
         r.insert(
             "path".to_string(),
-            UntaggedValue::path(d.path).retag(&d.tag),
+            UntaggedValue::path(d.path).into_value(&d.tag),
         );
 
         r.insert(
             "apparent".to_string(),
-            UntaggedValue::bytes(d.size).retag(&d.tag),
+            UntaggedValue::filesize(d.size).into_value(&d.tag),
         );
 
         r.insert(
             "physical".to_string(),
-            UntaggedValue::bytes(d.blocks).retag(&d.tag),
+            UntaggedValue::filesize(d.blocks).into_value(&d.tag),
         );
 
         r.insert("directories".to_string(), value_from_vec(d.dirs, &d.tag));
@@ -330,7 +376,7 @@ impl From<DirInfo> for Value {
                     .map(move |e| UntaggedValue::Error(e).into_untagged_value())
                     .collect::<Vec<Value>>(),
             )
-            .retag(&d.tag);
+            .into_value(&d.tag);
 
             r.insert("errors".to_string(), v);
         }
@@ -348,29 +394,45 @@ impl From<FileInfo> for Value {
 
         r.insert(
             "path".to_string(),
-            UntaggedValue::path(f.path).retag(&f.tag),
+            UntaggedValue::path(f.path).into_value(&f.tag),
         );
 
         r.insert(
             "apparent".to_string(),
-            UntaggedValue::bytes(f.size).retag(&f.tag),
+            UntaggedValue::filesize(f.size).into_value(&f.tag),
         );
 
         let b = f
             .blocks
-            .map(UntaggedValue::bytes)
+            .map(UntaggedValue::filesize)
             .unwrap_or_else(UntaggedValue::nothing)
-            .retag(&f.tag);
+            .into_value(&f.tag);
 
         r.insert("physical".to_string(), b);
 
         r.insert(
             "directories".to_string(),
-            UntaggedValue::nothing().retag(&f.tag),
+            UntaggedValue::nothing().into_value(&f.tag),
         );
 
-        r.insert("files".to_string(), UntaggedValue::nothing().retag(&f.tag));
+        r.insert(
+            "files".to_string(),
+            UntaggedValue::nothing().into_value(&f.tag),
+        );
 
-        UntaggedValue::row(r).retag(&f.tag)
+        UntaggedValue::row(r).into_value(&f.tag)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Du;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Du {})?)
     }
 }

crates/nu-cli/src/commands/each.rs

@@ -1,86 +0,0 @@
-use crate::commands::classified::block::run_block;
-use crate::commands::PerItemCommand;
-use crate::context::CommandRegistry;
-use crate::prelude::*;
-
-use futures::stream::once;
-
-use nu_errors::ShellError;
-use nu_protocol::{CallInfo, ReturnSuccess, Scope, Signature, SyntaxShape, UntaggedValue, Value};
-
-pub struct Each;
-
-impl PerItemCommand for Each {
-    fn name(&self) -> &str {
-        "each"
-    }
-
-    fn signature(&self) -> Signature {
-        Signature::build("each").required(
-            "block",
-            SyntaxShape::Block,
-            "the block to run on each row",
-        )
-    }
-
-    fn usage(&self) -> &str {
-        "Run a block on each row of the table."
-    }
-
-    fn run(
-        &self,
-        call_info: &CallInfo,
-        registry: &CommandRegistry,
-        raw_args: &RawCommandArgs,
-        input: Value,
-    ) -> Result<OutputStream, ShellError> {
-        let call_info = call_info.clone();
-        let registry = registry.clone();
-        let raw_args = raw_args.clone();
-        let stream = async_stream! {
-            match call_info.args.expect_nth(0)? {
-                Value {
-                    value: UntaggedValue::Block(block),
-                    tag
-                } => {
-                    let mut context = Context::from_raw(&raw_args, &registry);
-                    let input_clone = input.clone();
-                    let input_stream = once(async { Ok(input) }).to_input_stream();
-
-                    let result = run_block(
-                        block,
-                        &mut context,
-                        input_stream,
-                        &Scope::new(input_clone),
-                    ).await;
-
-                    match result {
-                        Ok(mut stream) => {
-                            let errors = context.get_errors();
-                            if let Some(error) = errors.first() {
-                                yield Err(error.clone());
-                                return;
-                            }
-
-                            while let Some(result) = stream.next().await {
-                                yield Ok(ReturnSuccess::Value(result));
-                            }
-                        }
-                        Err(e) => {
-                            yield Err(e);
-                        }
-                    }
-                }
-                Value { tag, .. } => {
-                    yield Err(ShellError::labeled_error(
-                        "Expected a block",
-                        "each needs a block",
-                        tag,
-                    ))
-                }
-            };
-        };
-
-        Ok(stream.to_output_stream())
-    }
-}

crates/nu-cli/src/commands/each/command.rs

@@ -0,0 +1,172 @@
+use crate::command_registry::CommandRegistry;
+use crate::commands::classified::block::run_block;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+
+use futures::stream::once;
+use nu_errors::ShellError;
+use nu_protocol::{
+    hir::Block, Scope, Signature, SyntaxShape, TaggedDictBuilder, UntaggedValue, Value,
+};
+use nu_source::Tagged;
+
+pub struct Each;
+
+#[derive(Deserialize)]
+pub struct EachArgs {
+    block: Block,
+    numbered: Tagged<bool>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for Each {
+    fn name(&self) -> &str {
+        "each"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("each")
+            .required("block", SyntaxShape::Block, "the block to run on each row")
+            .switch(
+                "numbered",
+                "returned a numbered item ($it.index and $it.item)",
+                Some('n'),
+            )
+    }
+
+    fn usage(&self) -> &str {
+        "Run a block on each row of the table."
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        each(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Echo the sum of each row",
+                example: "echo [[1 2] [3 4]] | each { echo $it | math sum }",
+                result: None,
+            },
+            Example {
+                description: "Echo the square of each integer",
+                example: "echo [1 2 3] | each { echo $(= $it * $it) }",
+                result: Some(vec![
+                    UntaggedValue::int(1).into(),
+                    UntaggedValue::int(4).into(),
+                    UntaggedValue::int(9).into(),
+                ]),
+            },
+            Example {
+                description: "Number each item and echo a message",
+                example:
+                    "echo ['bob' 'fred'] | each --numbered { echo `{{$it.index}} is {{$it.item}}` }",
+                result: Some(vec![Value::from("0 is bob"), Value::from("1 is fred")]),
+            },
+        ]
+    }
+}
+
+pub async fn process_row(
+    block: Arc<Block>,
+    scope: Arc<Scope>,
+    mut context: Arc<EvaluationContext>,
+    input: Value,
+) -> Result<OutputStream, ShellError> {
+    let input_clone = input.clone();
+    // When we process a row, we need to know whether the block wants to have the contents of the row as
+    // a parameter to the block (so it gets assigned to a variable that can be used inside the block) or
+    // if it wants the contents as as an input stream
+
+    let input_stream = if !block.params.is_empty() {
+        InputStream::empty()
+    } else {
+        once(async { Ok(input_clone) }).to_input_stream()
+    };
+
+    let scope = if !block.params.is_empty() {
+        // FIXME: add check for more than parameter, once that's supported
+        Scope::append_var(scope, block.params[0].clone(), input)
+    } else {
+        scope
+    };
+
+    Ok(
+        run_block(&block, Arc::make_mut(&mut context), input_stream, scope)
+            .await?
+            .to_output_stream(),
+    )
+}
+
+pub(crate) fn make_indexed_item(index: usize, item: Value) -> Value {
+    let mut dict = TaggedDictBuilder::new(item.tag());
+    dict.insert_untagged("index", UntaggedValue::int(index));
+    dict.insert_value("item", item);
+
+    dict.into_value()
+}
+
+async fn each(
+    raw_args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+    let scope = raw_args.call_info.scope.clone();
+    let context = Arc::new(EvaluationContext::from_raw(&raw_args, &registry));
+    let (each_args, input): (EachArgs, _) = raw_args.process(&registry).await?;
+    let block = Arc::new(each_args.block);
+
+    if each_args.numbered.item {
+        Ok(input
+            .enumerate()
+            .then(move |input| {
+                let block = block.clone();
+                let scope = scope.clone();
+                let context = context.clone();
+                let row = make_indexed_item(input.0, input.1);
+
+                async {
+                    match process_row(block, scope, context, row).await {
+                        Ok(s) => s,
+                        Err(e) => OutputStream::one(Err(e)),
+                    }
+                }
+            })
+            .flatten()
+            .to_output_stream())
+    } else {
+        Ok(input
+            .then(move |input| {
+                let block = block.clone();
+                let scope = scope.clone();
+                let context = context.clone();
+
+                async {
+                    match process_row(block, scope, context, input).await {
+                        Ok(s) => s,
+                        Err(e) => OutputStream::one(Err(e)),
+                    }
+                }
+            })
+            .flatten()
+            .to_output_stream())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Each;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Each {})?)
+    }
+}

crates/nu-cli/src/commands/each/group.rs

@@ -0,0 +1,123 @@
+use crate::commands::each::process_row;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{hir::Block, ReturnSuccess, Scope, Signature, SyntaxShape, UntaggedValue, Value};
+use nu_source::Tagged;
+use serde::Deserialize;
+
+pub struct EachGroup;
+
+#[derive(Deserialize)]
+pub struct EachGroupArgs {
+    group_size: Tagged<usize>,
+    block: Block,
+    //numbered: Tagged<bool>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for EachGroup {
+    fn name(&self) -> &str {
+        "each group"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("each group")
+            .required("group_size", SyntaxShape::Int, "the size of each group")
+            .required(
+                "block",
+                SyntaxShape::Block,
+                "the block to run on each group",
+            )
+    }
+
+    fn usage(&self) -> &str {
+        "Runs a block on groups of `group_size` rows of a table at a time."
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Echo the sum of each pair",
+            example: "echo [1 2 3 4] | each group 2 { echo $it | math sum }",
+            result: None,
+        }]
+    }
+
+    async fn run(
+        &self,
+        raw_args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        let registry = registry.clone();
+        let scope = raw_args.call_info.scope.clone();
+        let context = Arc::new(EvaluationContext::from_raw(&raw_args, &registry));
+        let (each_args, input): (EachGroupArgs, _) = raw_args.process(&registry).await?;
+        let block = Arc::new(each_args.block);
+
+        Ok(input
+            .chunks(each_args.group_size.item)
+            .then(move |input| {
+                run_block_on_vec(input, block.clone(), scope.clone(), context.clone())
+            })
+            .flatten()
+            .to_output_stream())
+    }
+}
+
+pub(crate) fn run_block_on_vec(
+    input: Vec<Value>,
+    block: Arc<Block>,
+    scope: Arc<Scope>,
+    context: Arc<EvaluationContext>,
+) -> impl Future<Output = OutputStream> {
+    let value = Value {
+        value: UntaggedValue::Table(input),
+        tag: Tag::unknown(),
+    };
+
+    async {
+        match process_row(block, scope, context, value).await {
+            Ok(s) => {
+                // We need to handle this differently depending on whether process_row
+                // returned just 1 value or if it returned multiple as a stream.
+                let vec = s.collect::<Vec<_>>().await;
+
+                // If it returned just one value, just take that value
+                if vec.len() == 1 {
+                    return OutputStream::one(vec.into_iter().next().expect(
+                        "This should be impossible, we just checked that vec.len() == 1.",
+                    ));
+                }
+
+                // If it returned multiple values, we need to put them into a table and
+                // return that.
+                let result = vec.into_iter().collect::<Result<Vec<ReturnSuccess>, _>>();
+                let result_table = match result {
+                    Ok(t) => t,
+                    Err(e) => return OutputStream::one(Err(e)),
+                };
+
+                let table = result_table
+                    .into_iter()
+                    .filter_map(|x| x.raw_value())
+                    .collect();
+
+                OutputStream::one(Ok(ReturnSuccess::Value(UntaggedValue::Table(table).into())))
+            }
+            Err(e) => OutputStream::one(Err(e)),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::EachGroup;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(EachGroup {})?)
+    }
+}

crates/nu-cli/src/commands/each/mod.rs

@@ -0,0 +1,9 @@
+pub mod command;
+pub mod group;
+pub mod window;
+
+pub(crate) use command::make_indexed_item;
+pub use command::process_row;
+pub use command::Each;
+pub use group::EachGroup;
+pub use window::EachWindow;

crates/nu-cli/src/commands/each/window.rs

@@ -0,0 +1,112 @@
+use crate::commands::each::group::run_block_on_vec;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+//use itertools::Itertools;
+use nu_errors::ShellError;
+use nu_protocol::{hir::Block, Primitive, Signature, SyntaxShape, UntaggedValue};
+use nu_source::Tagged;
+use serde::Deserialize;
+
+pub struct EachWindow;
+
+#[derive(Deserialize)]
+pub struct EachWindowArgs {
+    window_size: Tagged<usize>,
+    block: Block,
+    stride: Option<Tagged<usize>>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for EachWindow {
+    fn name(&self) -> &str {
+        "each window"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("each window")
+            .required("window_size", SyntaxShape::Int, "the size of each window")
+            .named(
+                "stride",
+                SyntaxShape::Int,
+                "the number of rows to slide over between windows",
+                Some('s'),
+            )
+            .required(
+                "block",
+                SyntaxShape::Block,
+                "the block to run on each group",
+            )
+    }
+
+    fn usage(&self) -> &str {
+        "Runs a block on sliding windows of `window_size` rows of a table at a time."
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Echo the sum of each window",
+            example: "echo [1 2 3 4] | each window 2 { echo $it | math sum }",
+            result: None,
+        }]
+    }
+
+    async fn run(
+        &self,
+        raw_args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        let registry = registry.clone();
+        let scope = raw_args.call_info.scope.clone();
+        let context = Arc::new(EvaluationContext::from_raw(&raw_args, &registry));
+        let (each_args, mut input): (EachWindowArgs, _) = raw_args.process(&registry).await?;
+        let block = Arc::new(each_args.block);
+
+        let mut window: Vec<_> = input
+            .by_ref()
+            .take(*each_args.window_size - 1)
+            .collect::<Vec<_>>()
+            .await;
+
+        // `window` must start with dummy values, which will be removed on the first iteration
+        let stride = each_args.stride.map(|x| *x).unwrap_or(1);
+        window.insert(0, UntaggedValue::Primitive(Primitive::Nothing).into());
+
+        Ok(input
+            .enumerate()
+            .then(move |(i, input)| {
+                // This would probably be more efficient if `last` was a VecDeque
+                // But we can't have that because it needs to be put into a Table
+                window.remove(0);
+                window.push(input);
+
+                let block = block.clone();
+                let scope = scope.clone();
+                let context = context.clone();
+                let local_window = window.clone();
+
+                async move {
+                    if i % stride == 0 {
+                        Some(run_block_on_vec(local_window, block, scope, context).await)
+                    } else {
+                        None
+                    }
+                }
+            })
+            .filter_map(|x| async { x })
+            .flatten()
+            .to_output_stream())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::EachWindow;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(EachWindow {})?)
+    }
+}

crates/nu-cli/src/commands/echo.rs

@@ -1,10 +1,20 @@
+use crate::commands::WholeStreamCommand;
 use crate::prelude::*;
 use nu_errors::ShellError;
-use nu_protocol::{CallInfo, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
+use nu_protocol::hir::Operator;
+use nu_protocol::{
+    Primitive, Range, RangeInclusion, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value,
+};
 
 pub struct Echo;
 
-impl PerItemCommand for Echo {
+#[derive(Deserialize)]
+pub struct EchoArgs {
+    pub rest: Vec<Value>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for Echo {
     fn name(&self) -> &str {
         "echo"
     }
@@ -17,51 +27,147 @@ impl PerItemCommand for Echo {
         "Echo the arguments back to the user."
     }
 
-    fn run(
+    async fn run(
         &self,
-        call_info: &CallInfo,
+        args: CommandArgs,
         registry: &CommandRegistry,
-        raw_args: &RawCommandArgs,
-        _input: Value,
     ) -> Result<OutputStream, ShellError> {
-        run(call_info, registry, raw_args)
+        echo(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Put a hello message in the pipeline",
+                example: "echo 'hello'",
+                result: Some(vec![Value::from("hello")]),
+            },
+            Example {
+                description: "Print the value of the special '$nu' variable",
+                example: "echo $nu",
+                result: None,
+            },
+        ]
     }
 }
 
-fn run(
-    call_info: &CallInfo,
-    _registry: &CommandRegistry,
-    _raw_args: &RawCommandArgs,
-) -> Result<OutputStream, ShellError> {
-    let mut output = vec![];
+async fn echo(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+    let (args, _): (EchoArgs, _) = args.process(&registry).await?;
 
-    if let Some(ref positional) = call_info.args.positional {
-        for i in positional {
-            match i.as_string() {
-                Ok(s) => {
-                    output.push(Ok(ReturnSuccess::Value(
-                        UntaggedValue::string(s).into_value(i.tag.clone()),
-                    )));
-                }
-                _ => match i {
-                    Value {
-                        value: UntaggedValue::Table(table),
-                        ..
-                    } => {
-                        for value in table {
-                            output.push(Ok(ReturnSuccess::Value(value.clone())));
-                        }
-                    }
-                    _ => {
-                        output.push(Ok(ReturnSuccess::Value(i.clone())));
-                    }
-                },
-            }
+    let stream = args.rest.into_iter().map(|i| match i.as_string() {
+        Ok(s) => OutputStream::one(Ok(ReturnSuccess::Value(
+            UntaggedValue::string(s).into_value(i.tag.clone()),
+        ))),
+        _ => match i {
+            Value {
+                value: UntaggedValue::Table(table),
+                ..
+            } => futures::stream::iter(table.into_iter().map(ReturnSuccess::value))
+                .to_output_stream(),
+            Value {
+                value: UntaggedValue::Primitive(Primitive::Range(range)),
+                tag,
+            } => futures::stream::iter(RangeIterator::new(*range, tag)).to_output_stream(),
+            _ => OutputStream::one(Ok(ReturnSuccess::Value(i.clone()))),
+        },
+    });
+
+    Ok(futures::stream::iter(stream).flatten().to_output_stream())
+}
+
+struct RangeIterator {
+    curr: Primitive,
+    end: Primitive,
+    tag: Tag,
+    is_end_inclusive: bool,
+}
+
+impl RangeIterator {
+    pub fn new(range: Range, tag: Tag) -> RangeIterator {
+        let start = match range.from.0.item {
+            Primitive::Nothing => Primitive::Int(0.into()),
+            x => x,
+        };
+
+        RangeIterator {
+            curr: start,
+            end: range.to.0.item,
+            tag,
+            is_end_inclusive: matches!(range.to.1, RangeInclusion::Inclusive),
         }
     }
-
-    // TODO: This whole block can probably be replaced with `.map()`
-    let stream = futures::stream::iter(output);
-
-    Ok(stream.to_output_stream())
+}
+
+impl Iterator for RangeIterator {
+    type Item = Result<ReturnSuccess, ShellError>;
+    fn next(&mut self) -> Option<Self::Item> {
+        let ordering = if self.end == Primitive::Nothing {
+            Ordering::Less
+        } else {
+            let result =
+                nu_data::base::coerce_compare_primitive(&self.curr, &self.end).map_err(|_| {
+                    ShellError::labeled_error(
+                        "Cannot create range",
+                        "unsupported range",
+                        self.tag.span,
+                    )
+                });
+
+            if let Err(result) = result {
+                return Some(Err(result));
+            }
+
+            let result = result
+                .expect("Internal error: the error case was already protected, but that failed");
+
+            result.compare()
+        };
+
+        use std::cmp::Ordering;
+
+        if (ordering == Ordering::Less) || (self.is_end_inclusive && ordering == Ordering::Equal) {
+            let output = UntaggedValue::Primitive(self.curr.clone()).into_value(self.tag.clone());
+
+            let next_value = nu_data::value::compute_values(
+                Operator::Plus,
+                &UntaggedValue::Primitive(self.curr.clone()),
+                &UntaggedValue::int(1),
+            );
+
+            self.curr = match next_value {
+                Ok(result) => match result {
+                    UntaggedValue::Primitive(p) => p,
+                    _ => {
+                        return Some(Err(ShellError::unimplemented(
+                            "Internal error: expected a primitive result from increment",
+                        )));
+                    }
+                },
+                Err((left_type, right_type)) => {
+                    return Some(Err(ShellError::coerce_error(
+                        left_type.spanned(self.tag.span),
+                        right_type.spanned(self.tag.span),
+                    )));
+                }
+            };
+            Some(ReturnSuccess::value(output))
+        } else {
+            // TODO: add inclusive/exclusive ranges
+            None
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Echo;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Echo {})?)
+    }
 }

crates/nu-cli/src/commands/edit.rs

@@ -1,72 +0,0 @@
-use crate::commands::PerItemCommand;
-use crate::context::CommandRegistry;
-use crate::prelude::*;
-use nu_errors::ShellError;
-use nu_protocol::{CallInfo, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
-use nu_value_ext::ValueExt;
-
-pub struct Edit;
-
-impl PerItemCommand for Edit {
-    fn name(&self) -> &str {
-        "edit"
-    }
-
-    fn signature(&self) -> Signature {
-        Signature::build("edit")
-            .required(
-                "Field",
-                SyntaxShape::ColumnPath,
-                "the name of the column to edit",
-            )
-            .required(
-                "Value",
-                SyntaxShape::String,
-                "the new value to give the cell(s)",
-            )
-    }
-
-    fn usage(&self) -> &str {
-        "Edit an existing column to have a new value."
-    }
-
-    fn run(
-        &self,
-        call_info: &CallInfo,
-        _registry: &CommandRegistry,
-        _raw_args: &RawCommandArgs,
-        value: Value,
-    ) -> Result<OutputStream, ShellError> {
-        let value_tag = value.tag();
-        let field = call_info.args.expect_nth(0)?.as_column_path()?;
-        let replacement = call_info.args.expect_nth(1)?.tagged_unknown();
-
-        let stream = match value {
-            obj
-            @
-            Value {
-                value: UntaggedValue::Row(_),
-                ..
-            } => match obj.replace_data_at_column_path(&field, replacement.item.clone()) {
-                Some(v) => futures::stream::iter(vec![Ok(ReturnSuccess::Value(v))]),
-                None => {
-                    return Err(ShellError::labeled_error(
-                        "edit could not find place to insert column",
-                        "column name",
-                        &field.tag,
-                    ))
-                }
-            },
-
-            _ => {
-                return Err(ShellError::labeled_error(
-                    "Unrecognized type in stream",
-                    "original value",
-                    value_tag,
-                ))
-            }
-        };
-
-        Ok(stream.to_output_stream())
-    }
-}

crates/nu-cli/src/commands/empty.rs

@@ -0,0 +1,288 @@
+use crate::command_registry::CommandRegistry;
+use crate::commands::classified::block::run_block;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{
+    hir::Block, ColumnPath, Primitive, ReturnSuccess, Scope, Signature, SyntaxShape, UntaggedValue,
+    Value,
+};
+use nu_source::Tagged;
+use nu_value_ext::{as_string, ValueExt};
+
+use futures::stream::once;
+use indexmap::indexmap;
+
+#[derive(Deserialize)]
+pub struct Arguments {
+    rest: Vec<Value>,
+}
+
+pub struct Command;
+
+#[async_trait]
+impl WholeStreamCommand for Command {
+    fn name(&self) -> &str {
+        "empty?"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("empty?").rest(
+            SyntaxShape::Any,
+            "the names of the columns to check emptiness. Pass an optional block to replace if empty",
+        )
+    }
+
+    fn usage(&self) -> &str {
+        "Check for empty values"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        is_empty(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Check if a value is empty",
+                example: "echo '' | empty?",
+                result: Some(vec![UntaggedValue::boolean(true).into()]),
+            },
+            Example {
+                description: "more than one column",
+                example: "echo [[meal size]; [arepa small] [taco '']] | empty? meal size",
+                result: Some(
+                    vec![
+                        UntaggedValue::row(indexmap! {
+                                "meal".to_string() => Value::from(false),
+                                "size".to_string() => Value::from(false),
+                        })
+                        .into(),
+                        UntaggedValue::row(indexmap! {
+                                "meal".to_string() => Value::from(false),
+                                "size".to_string() => Value::from(true),
+                        })
+                        .into(),
+                    ],
+                ),
+            },Example {
+                description: "use a block if setting the empty cell contents is wanted",
+                example: "echo [[2020/04/16 2020/07/10 2020/11/16]; ['' [27] [37]]] | empty? 2020/04/16 { = [33 37] }",
+                result: Some(
+                    vec![
+                        UntaggedValue::row(indexmap! {
+                                "2020/04/16".to_string() => UntaggedValue::table(&[UntaggedValue::int(33).into(), UntaggedValue::int(37).into()]).into(),
+                                "2020/07/10".to_string() => UntaggedValue::table(&[UntaggedValue::int(27).into()]).into(),
+                                "2020/11/16".to_string() => UntaggedValue::table(&[UntaggedValue::int(37).into()]).into(),
+                        })
+                        .into(),
+                    ],
+                ),
+            },
+        ]
+    }
+}
+
+async fn is_empty(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let tag = args.call_info.name_tag.clone();
+    let name_tag = Arc::new(args.call_info.name_tag.clone());
+    let context = Arc::new(EvaluationContext::from_raw(&args, &registry));
+    let scope = args.call_info.scope.clone();
+    let (Arguments { rest }, input) = args.process(&registry).await?;
+    let (columns, default_block): (Vec<ColumnPath>, Option<Block>) = arguments(rest)?;
+    let default_block = Arc::new(default_block);
+
+    if input.is_empty() {
+        let stream = futures::stream::iter(vec![
+            UntaggedValue::Primitive(Primitive::Nothing).into_value(tag)
+        ]);
+
+        return Ok(InputStream::from_stream(stream)
+            .then(move |input| {
+                let tag = name_tag.clone();
+                let scope = scope.clone();
+                let context = context.clone();
+                let block = default_block.clone();
+                let columns = vec![];
+
+                async {
+                    match process_row(scope, context, input, block, columns, tag).await {
+                        Ok(s) => s,
+                        Err(e) => OutputStream::one(Err(e)),
+                    }
+                }
+            })
+            .flatten()
+            .to_output_stream());
+    }
+
+    Ok(input
+        .then(move |input| {
+            let tag = name_tag.clone();
+            let scope = scope.clone();
+            let context = context.clone();
+            let block = default_block.clone();
+            let columns = columns.clone();
+
+            async {
+                match process_row(scope, context, input, block, columns, tag).await {
+                    Ok(s) => s,
+                    Err(e) => OutputStream::one(Err(e)),
+                }
+            }
+        })
+        .flatten()
+        .to_output_stream())
+}
+
+fn arguments(rest: Vec<Value>) -> Result<(Vec<ColumnPath>, Option<Block>), ShellError> {
+    let mut rest = rest;
+    let mut columns = vec![];
+    let mut default = None;
+
+    let last_argument = rest.pop();
+
+    match last_argument {
+        Some(Value {
+            value: UntaggedValue::Block(call),
+            ..
+        }) => default = Some(call),
+        Some(other) => {
+            let Tagged { item: path, .. } = other.as_column_path()?;
+
+            columns = vec![path];
+        }
+        None => {}
+    };
+
+    for argument in rest {
+        let Tagged { item: path, .. } = argument.as_column_path()?;
+
+        columns.push(path);
+    }
+
+    Ok((columns, default))
+}
+
+async fn process_row(
+    scope: Arc<Scope>,
+    mut context: Arc<EvaluationContext>,
+    input: Value,
+    default_block: Arc<Option<Block>>,
+    column_paths: Vec<ColumnPath>,
+    tag: Arc<Tag>,
+) -> Result<OutputStream, ShellError> {
+    let _tag = &*tag;
+    let mut out = Arc::new(None);
+    let results = Arc::make_mut(&mut out);
+
+    if let Some(default_block) = &*default_block {
+        let for_block = input.clone();
+        let input_stream = once(async { Ok(for_block) }).to_input_stream();
+
+        let scope = Scope::append_var(scope, "$it", input.clone());
+
+        let mut stream = run_block(
+            &default_block,
+            Arc::make_mut(&mut context),
+            input_stream,
+            scope,
+        )
+        .await?;
+
+        *results = Some({
+            let values = stream.drain_vec().await;
+
+            let errors = context.get_errors();
+
+            if let Some(error) = errors.first() {
+                return Err(error.clone());
+            }
+
+            if values.len() == 1 {
+                let value = values
+                    .get(0)
+                    .ok_or_else(|| ShellError::unexpected("No value."))?;
+
+                Value {
+                    value: value.value.clone(),
+                    tag: input.tag.clone(),
+                }
+            } else if values.is_empty() {
+                UntaggedValue::nothing().into_value(&input.tag)
+            } else {
+                UntaggedValue::table(&values).into_value(&input.tag)
+            }
+        });
+    }
+
+    match input {
+        Value {
+            value: UntaggedValue::Row(ref r),
+            ref tag,
+        } => {
+            if column_paths.is_empty() {
+                Ok(OutputStream::one(ReturnSuccess::value({
+                    let is_empty = input.is_empty();
+
+                    if default_block.is_some() {
+                        if is_empty {
+                            results
+                                .clone()
+                                .unwrap_or_else(|| UntaggedValue::boolean(true).into_value(tag))
+                        } else {
+                            input.clone()
+                        }
+                    } else {
+                        UntaggedValue::boolean(is_empty).into_value(tag)
+                    }
+                })))
+            } else {
+                let mut obj = input.clone();
+
+                for column in column_paths.clone() {
+                    let path = UntaggedValue::Primitive(Primitive::ColumnPath(column.clone()))
+                        .into_value(tag);
+                    let data = r.get_data(&as_string(&path)?).borrow().clone();
+                    let is_empty = data.is_empty();
+
+                    let default = if default_block.is_some() {
+                        if is_empty {
+                            results
+                                .clone()
+                                .unwrap_or_else(|| UntaggedValue::boolean(true).into_value(tag))
+                        } else {
+                            data.clone()
+                        }
+                    } else {
+                        UntaggedValue::boolean(is_empty).into_value(tag)
+                    };
+
+                    if let Ok(value) =
+                        obj.swap_data_by_column_path(&column, Box::new(move |_| Ok(default)))
+                    {
+                        obj = value;
+                    }
+                }
+
+                Ok(OutputStream::one(ReturnSuccess::value(obj)))
+            }
+        }
+        other => Ok(OutputStream::one(ReturnSuccess::value({
+            if other.is_empty() {
+                results
+                    .clone()
+                    .unwrap_or_else(|| UntaggedValue::boolean(true).into_value(other.tag))
+            } else {
+                UntaggedValue::boolean(false).into_value(other.tag)
+            }
+        }))),
+    }
+}

crates/nu-cli/src/commands/enter.rs

@@ -1,157 +1,202 @@
-use crate::commands::PerItemCommand;
+use crate::command_registry::CommandRegistry;
 use crate::commands::UnevaluatedCallInfo;
-use crate::context::CommandRegistry;
+use crate::commands::WholeStreamCommand;
 use crate::prelude::*;
 use nu_errors::ShellError;
+use nu_protocol::hir::ExternalRedirection;
 use nu_protocol::{
-    CallInfo, CommandAction, Primitive, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value,
+    CommandAction, Primitive, ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value,
 };
+use nu_source::Tagged;
+use std::path::PathBuf;
 
 pub struct Enter;
 
-impl PerItemCommand for Enter {
+#[derive(Deserialize)]
+pub struct EnterArgs {
+    location: Tagged<PathBuf>,
+    encoding: Option<Tagged<String>>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for Enter {
     fn name(&self) -> &str {
         "enter"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("enter").required(
-            "location",
-            SyntaxShape::Path,
-            "the location to create a new shell from",
-        )
+        Signature::build("enter")
+            .required(
+                "location",
+                SyntaxShape::Path,
+                "the location to create a new shell from",
+            )
+            .named(
+                "encoding",
+                SyntaxShape::String,
+                "encoding to use to open file",
+                Some('e'),
+            )
     }
 
     fn usage(&self) -> &str {
-        "Create a new shell and begin at this path."
+        r#"Create a new shell and begin at this path.
+        
+Multiple encodings are supported for reading text files by using
+the '--encoding <encoding>' parameter. Here is an example of a few:
+big5, euc-jp, euc-kr, gbk, iso-8859-1, utf-16, cp1252, latin5
+
+For a more complete list of encodings please refer to the encoding_rs
+documentation link at https://docs.rs/encoding_rs/0.8.23/encoding_rs/#statics"#
     }
 
-    fn run(
+    async fn run(
         &self,
-        call_info: &CallInfo,
+        args: CommandArgs,
         registry: &CommandRegistry,
-        raw_args: &RawCommandArgs,
-        _input: Value,
     ) -> Result<OutputStream, ShellError> {
-        let registry = registry.clone();
-        let raw_args = raw_args.clone();
-        match call_info.args.expect_nth(0)? {
-            Value {
-                value: UntaggedValue::Primitive(Primitive::Path(location)),
-                tag,
-                ..
-            } => {
-                let location_string = location.display().to_string();
-                let location_clone = location_string.clone();
-                let tag_clone = tag.clone();
+        enter(args, registry).await
+    }
 
-                if location_string.starts_with("help") {
-                    let spec = location_string.split(':').collect::<Vec<&str>>();
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Enter a path as a new shell",
+                example: "enter ../projectB",
+                result: None,
+            },
+            Example {
+                description: "Enter a file as a new shell",
+                example: "enter package.json",
+                result: None,
+            },
+            Example {
+                description: "Enters file with iso-8859-1 encoding",
+                example: "enter file.csv --encoding iso-8859-1",
+                result: None,
+            },
+        ]
+    }
+}
 
-                    if spec.len() == 2 {
-                        let (_, command) = (spec[0], spec[1]);
+async fn enter(
+    raw_args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+    let scope = raw_args.call_info.scope.clone();
+    let shell_manager = raw_args.shell_manager.clone();
+    let head = raw_args.call_info.args.head.clone();
+    let ctrl_c = raw_args.ctrl_c.clone();
+    let current_errors = raw_args.current_errors.clone();
+    let host = raw_args.host.clone();
+    let tag = raw_args.call_info.name_tag.clone();
+    let (EnterArgs { location, encoding }, _) = raw_args.process(&registry).await?;
+    let location_string = location.display().to_string();
+    let location_clone = location_string.clone();
 
-                        if registry.has(command) {
-                            return Ok(vec![Ok(ReturnSuccess::Action(
-                                CommandAction::EnterHelpShell(
-                                    UntaggedValue::string(command).into_value(Tag::unknown()),
+    if location_string.starts_with("help") {
+        let spec = location_string.split(':').collect::<Vec<&str>>();
+
+        if spec.len() == 2 {
+            let (_, command) = (spec[0], spec[1]);
+
+            if registry.has(command) {
+                return Ok(OutputStream::one(ReturnSuccess::action(
+                    CommandAction::EnterHelpShell(
+                        UntaggedValue::string(command).into_value(Tag::unknown()),
+                    ),
+                )));
+            }
+        }
+        Ok(OutputStream::one(ReturnSuccess::action(
+            CommandAction::EnterHelpShell(UntaggedValue::nothing().into_value(Tag::unknown())),
+        )))
+    } else if location.is_dir() {
+        Ok(OutputStream::one(ReturnSuccess::action(
+            CommandAction::EnterShell(location_clone),
+        )))
+    } else {
+        // If it's a file, attempt to open the file as a value and enter it
+        let cwd = shell_manager.path();
+
+        let full_path = std::path::PathBuf::from(cwd);
+
+        let (file_extension, tagged_contents) = crate::commands::open::fetch(
+            &full_path,
+            &PathBuf::from(location_clone),
+            tag.span,
+            encoding,
+        )
+        .await?;
+
+        match tagged_contents.value {
+            UntaggedValue::Primitive(Primitive::String(_)) => {
+                if let Some(extension) = file_extension {
+                    let command_name = format!("from {}", extension);
+                    if let Some(converter) = registry.get_command(&command_name) {
+                        let new_args = RawCommandArgs {
+                            host,
+                            ctrl_c,
+                            current_errors,
+                            shell_manager,
+                            call_info: UnevaluatedCallInfo {
+                                args: nu_protocol::hir::Call {
+                                    head,
+                                    positional: None,
+                                    named: None,
+                                    span: Span::unknown(),
+                                    external_redirection: ExternalRedirection::Stdout,
+                                },
+                                name_tag: tag.clone(),
+                                scope: scope.clone(),
+                            },
+                        };
+                        let tag = tagged_contents.tag.clone();
+                        let mut result = converter
+                            .run(new_args.with_input(vec![tagged_contents]), &registry)
+                            .await?;
+                        let result_vec: Vec<Result<ReturnSuccess, ShellError>> =
+                            result.drain_vec().await;
+                        Ok(futures::stream::iter(result_vec.into_iter().map(
+                            move |res| match res {
+                                Ok(ReturnSuccess::Value(Value { value, .. })) => Ok(
+                                    ReturnSuccess::Action(CommandAction::EnterValueShell(Value {
+                                        value,
+                                        tag: tag.clone(),
+                                    })),
                                 ),
-                            ))]
-                            .into());
-                        }
+                                x => x,
+                            },
+                        ))
+                        .to_output_stream())
+                    } else {
+                        Ok(OutputStream::one(ReturnSuccess::action(
+                            CommandAction::EnterValueShell(tagged_contents),
+                        )))
                     }
-                    Ok(vec![Ok(ReturnSuccess::Action(CommandAction::EnterHelpShell(
-                        UntaggedValue::nothing().into_value(Tag::unknown()),
-                    )))]
-                    .into())
-                } else if location.is_dir() {
-                    Ok(vec![Ok(ReturnSuccess::Action(CommandAction::EnterShell(
-                        location_clone,
-                    )))]
-                    .into())
                 } else {
-                    let stream = async_stream! {
-                        // If it's a file, attempt to open the file as a value and enter it
-                        let cwd = raw_args.shell_manager.path();
-
-                        let full_path = std::path::PathBuf::from(cwd);
-
-                        let (file_extension, contents, contents_tag) =
-                            crate::commands::open::fetch(
-                                &full_path,
-                                &location_clone,
-                                tag_clone.span,
-                            ).await?;
-
-                        match contents {
-                            UntaggedValue::Primitive(Primitive::String(_)) => {
-                                let tagged_contents = contents.into_value(&contents_tag);
-
-                                if let Some(extension) = file_extension {
-                                    let command_name = format!("from-{}", extension);
-                                    if let Some(converter) =
-                                        registry.get_command(&command_name)
-                                    {
-                                        let new_args = RawCommandArgs {
-                                            host: raw_args.host,
-                                            ctrl_c: raw_args.ctrl_c,
-                                            shell_manager: raw_args.shell_manager,
-                                            call_info: UnevaluatedCallInfo {
-                                                args: nu_protocol::hir::Call {
-                                                    head: raw_args.call_info.args.head,
-                                                    positional: None,
-                                                    named: None,
-                                                    span: Span::unknown(),
-                                                    is_last: false,
-                                                },
-                                                name_tag: raw_args.call_info.name_tag,
-                                                scope: raw_args.call_info.scope.clone()
-                                            },
-                                        };
-                                        let mut result = converter.run(
-                                            new_args.with_input(vec![tagged_contents]),
-                                            &registry,
-                                        );
-                                        let result_vec: Vec<Result<ReturnSuccess, ShellError>> =
-                                            result.drain_vec().await;
-                                        for res in result_vec {
-                                            match res {
-                                                Ok(ReturnSuccess::Value(Value {
-                                                    value,
-                                                    ..
-                                                })) => {
-                                                    yield Ok(ReturnSuccess::Action(CommandAction::EnterValueShell(
-                                                        Value {
-                                                            value,
-                                                            tag: contents_tag.clone(),
-                                                        })));
-                                                }
-                                                x => yield x,
-                                            }
-                                        }
-                                    } else {
-                                        yield Ok(ReturnSuccess::Action(CommandAction::EnterValueShell(tagged_contents)));
-                                    }
-                                } else {
-                                    yield Ok(ReturnSuccess::Action(CommandAction::EnterValueShell(tagged_contents)));
-                                }
-                            }
-                            _ => {
-                                let tagged_contents = contents.into_value(contents_tag);
-
-                                yield Ok(ReturnSuccess::Action(CommandAction::EnterValueShell(tagged_contents)));
-                            }
-                        }
-                    };
-                    Ok(stream.to_output_stream())
+                    Ok(OutputStream::one(ReturnSuccess::action(
+                        CommandAction::EnterValueShell(tagged_contents),
+                    )))
                 }
             }
-            x => Ok(
-                vec![Ok(ReturnSuccess::Action(CommandAction::EnterValueShell(
-                    x.clone(),
-                )))]
-                .into(),
-            ),
+            _ => Ok(OutputStream::one(ReturnSuccess::action(
+                CommandAction::EnterValueShell(tagged_contents),
+            ))),
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::Enter;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Enter {})?)
+    }
+}

crates/nu-cli/src/commands/evaluate_by.rs

@@ -1,72 +0,0 @@
-use crate::commands::WholeStreamCommand;
-use crate::prelude::*;
-use crate::utils::data_processing::{evaluate, fetch};
-use nu_errors::ShellError;
-use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue, Value};
-use nu_source::{SpannedItem, Tagged};
-use nu_value_ext::ValueExt;
-
-pub struct EvaluateBy;
-
-#[derive(Deserialize)]
-pub struct EvaluateByArgs {
-    evaluate_with: Option<Tagged<String>>,
-}
-
-impl WholeStreamCommand for EvaluateBy {
-    fn name(&self) -> &str {
-        "evaluate-by"
-    }
-
-    fn signature(&self) -> Signature {
-        Signature::build("evaluate-by").named(
-            "evaluate_with",
-            SyntaxShape::String,
-            "the name of the column to evaluate by",
-            Some('w'),
-        )
-    }
-
-    fn usage(&self) -> &str {
-        "Creates a new table with the data from the tables rows evaluated by the column given."
-    }
-
-    fn run(
-        &self,
-        args: CommandArgs,
-        registry: &CommandRegistry,
-    ) -> Result<OutputStream, ShellError> {
-        args.process(registry, evaluate_by)?.run()
-    }
-}
-
-pub fn evaluate_by(
-    EvaluateByArgs { evaluate_with }: EvaluateByArgs,
-    RunnableContext { input, name, .. }: RunnableContext,
-) -> Result<OutputStream, ShellError> {
-    let stream = async_stream! {
-        let values: Vec<Value> = input.collect().await;
-
-        if values.is_empty() {
-            yield Err(ShellError::labeled_error(
-                    "Expected table from pipeline",
-                    "requires a table input",
-                    name
-                ))
-        } else {
-
-            let evaluate_with = if let Some(evaluator) = evaluate_with {
-                Some(evaluator.item().clone())
-            } else {
-                None
-            };
-
-            match evaluate(&values[0], evaluate_with, name) {
-                Ok(evaluated) => yield ReturnSuccess::value(evaluated),
-                Err(err) => yield Err(err)
-            }
-        }
-    };
-
-    Ok(stream.to_output_stream())
-}

crates/nu-cli/src/commands/every.rs

@@ -0,0 +1,104 @@
+use crate::command_registry::CommandRegistry;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{ReturnSuccess, Signature, SyntaxShape, UntaggedValue};
+use nu_source::Tagged;
+
+pub struct Every;
+
+#[derive(Deserialize)]
+pub struct EveryArgs {
+    stride: Tagged<u64>,
+    skip: Tagged<bool>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for Every {
+    fn name(&self) -> &str {
+        "every"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build(self.name())
+            .required(
+                "stride",
+                SyntaxShape::Int,
+                "how many rows to skip between (and including) each row returned",
+            )
+            .switch(
+                "skip",
+                "skip the rows that would be returned, instead of selecting them",
+                Some('s'),
+            )
+    }
+
+    fn usage(&self) -> &str {
+        "Show (or skip) every n-th row, starting from the first one."
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        every(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Get every second row",
+                example: "echo [1 2 3 4 5] | every 2",
+                result: Some(vec![
+                    UntaggedValue::int(1).into(),
+                    UntaggedValue::int(3).into(),
+                    UntaggedValue::int(5).into(),
+                ]),
+            },
+            Example {
+                description: "Skip every second row",
+                example: "echo [1 2 3 4 5] | every 2 --skip",
+                result: Some(vec![
+                    UntaggedValue::int(2).into(),
+                    UntaggedValue::int(4).into(),
+                ]),
+            },
+        ]
+    }
+}
+
+async fn every(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+    let (EveryArgs { stride, skip }, input) = args.process(&registry).await?;
+
+    let stride = stride.item;
+    let skip = skip.item;
+
+    Ok(input
+        .enumerate()
+        .filter_map(move |(i, value)| async move {
+            let stride_desired = if stride < 1 { 1 } else { stride } as usize;
+            let should_include = skip == (i % stride_desired != 0);
+
+            if should_include {
+                Some(ReturnSuccess::value(value))
+            } else {
+                None
+            }
+        })
+        .to_output_stream())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Every;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Every {})?)
+    }
+}

crates/nu-cli/src/commands/exec.rs

@@ -0,0 +1,87 @@
+use crate::command_registry::CommandRegistry;
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::{Signature, SyntaxShape};
+use nu_source::Tagged;
+use std::path::PathBuf;
+
+pub struct Exec;
+
+#[derive(Deserialize)]
+pub struct ExecArgs {
+    pub command: Tagged<PathBuf>,
+    pub rest: Vec<Tagged<String>>,
+}
+
+#[async_trait]
+impl WholeStreamCommand for Exec {
+    fn name(&self) -> &str {
+        "exec"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("exec")
+            .required("command", SyntaxShape::Path, "the command to execute")
+            .rest(SyntaxShape::Pattern, "any additional arguments for command")
+    }
+
+    fn usage(&self) -> &str {
+        "Execute command"
+    }
+
+    async fn run(
+        &self,
+        args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        exec(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Execute 'ps aux'",
+                example: "exec ps aux",
+                result: None,
+            },
+            Example {
+                description: "Execute 'nautilus'",
+                example: "exec nautilus",
+                result: None,
+            },
+        ]
+    }
+}
+
+#[cfg(unix)]
+async fn exec(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
+    use std::os::unix::process::CommandExt;
+    use std::process::Command;
+
+    let registry = registry.clone();
+    let name = args.call_info.name_tag.clone();
+    let (args, _): (ExecArgs, _) = args.process(&registry).await?;
+
+    let mut command = Command::new(args.command.item);
+    for tagged_arg in args.rest {
+        command.arg(tagged_arg.item);
+    }
+
+    let err = command.exec(); // this replaces our process, should not return
+
+    Err(ShellError::labeled_error(
+        "Error on exec",
+        format!("{}", err),
+        &name,
+    ))
+}
+
+#[cfg(not(unix))]
+async fn exec(args: CommandArgs, _registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
+    Err(ShellError::labeled_error(
+        "Error on exec",
+        "exec is not supported on your platform",
+        &args.call_info.name_tag,
+    ))
+}

crates/nu-cli/src/commands/exit.rs

@@ -1,11 +1,12 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::command::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
 use nu_protocol::{CommandAction, ReturnSuccess, Signature};
 
 pub struct Exit;
 
+#[async_trait]
 impl WholeStreamCommand for Exit {
     fn name(&self) -> &str {
         "exit"
@@ -19,21 +20,55 @@ impl WholeStreamCommand for Exit {
         "Exit the current shell (or all shells)"
     }
 
-    fn run(
+    async fn run(
         &self,
         args: CommandArgs,
         registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
-        exit(args, registry)
+        exit(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Exit the current shell",
+                example: "exit",
+                result: None,
+            },
+            Example {
+                description: "Exit all shells (exiting Nu)",
+                example: "exit --now",
+                result: None,
+            },
+        ]
     }
 }
 
-pub fn exit(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
-    let args = args.evaluate_once(registry)?;
+pub async fn exit(
+    args: CommandArgs,
+    registry: &CommandRegistry,
+) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+    let args = args.evaluate_once(&registry).await?;
 
-    if args.call_info.args.has("now") {
-        Ok(vec![Ok(ReturnSuccess::Action(CommandAction::Exit))].into())
+    let command_action = if args.call_info.args.has("now") {
+        CommandAction::Exit
     } else {
-        Ok(vec![Ok(ReturnSuccess::Action(CommandAction::LeaveShell))].into())
+        CommandAction::LeaveShell
+    };
+
+    Ok(OutputStream::one(ReturnSuccess::action(command_action)))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Exit;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(Exit {})?)
     }
 }

crates/nu-cli/src/commands/first.rs

@@ -1,8 +1,8 @@
+use crate::command_registry::CommandRegistry;
 use crate::commands::WholeStreamCommand;
-use crate::context::CommandRegistry;
 use crate::prelude::*;
 use nu_errors::ShellError;
-use nu_protocol::{Signature, SyntaxShape};
+use nu_protocol::{Signature, SyntaxShape, UntaggedValue};
 use nu_source::Tagged;
 
 pub struct First;
@@ -12,6 +12,7 @@ pub struct FirstArgs {
     rows: Option<Tagged<usize>>,
 }
 
+#[async_trait]
 impl WholeStreamCommand for First {
     fn name(&self) -> &str {
         "first"
@@ -29,24 +30,54 @@ impl WholeStreamCommand for First {
         "Show only the first number of rows."
     }
 
-    fn run(
+    async fn run(
         &self,
         args: CommandArgs,
         registry: &CommandRegistry,
     ) -> Result<OutputStream, ShellError> {
-        args.process(registry, first)?.run()
+        first(args, registry).await
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![
+            Example {
+                description: "Return the first item of a list/table",
+                example: "echo [1 2 3] | first",
+                result: Some(vec![UntaggedValue::int(1).into()]),
+            },
+            Example {
+                description: "Return the first 2 items of a list/table",
+                example: "echo [1 2 3] | first 2",
+                result: Some(vec![
+                    UntaggedValue::int(1).into(),
+                    UntaggedValue::int(2).into(),
+                ]),
+            },
+        ]
     }
 }
 
-fn first(
-    FirstArgs { rows }: FirstArgs,
-    context: RunnableContext,
-) -> Result<OutputStream, ShellError> {
+async fn first(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
+    let registry = registry.clone();
+    let (FirstArgs { rows }, input) = args.process(&registry).await?;
     let rows_desired = if let Some(quantity) = rows {
         *quantity
     } else {
         1
     };
 
-    Ok(OutputStream::from_input(context.input.take(rows_desired)))
+    Ok(input.take(rows_desired).to_output_stream())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::First;
+    use super::ShellError;
+
+    #[test]
+    fn examples_work_as_expected() -> Result<(), ShellError> {
+        use crate::examples::test as test_examples;
+
+        Ok(test_examples(First {})?)
+    }
 }