nushell/README.md

Nu Shell

A modern shell for the GitHub era.

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. Future releases will work to fill out missing features and improve stability. 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

There are a few good resources to learn about Nu. There is a book about Nu that is currently in progress. The book focuses on using Nu and its core concepts.

If you're a developer who would like to contribute to Nu, we're also working on a book for developers to help you get started. There are also good first issues to help you dive in.

We also have an active Discord and Twitter if you'd like to come and chat with us.

Try it in Gitpod.

Installation

Local

Up-to-date installation instructions can be found in the installation chapter of the book.

To build Nu, you will need to use the nightly version of the compiler.

Required dependencies:

• pkg-config and libssl (only needed on Linux)
  • 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

To install Nu via cargo (make sure you have installed rustup and the nightly compiler via rustup install nightly):

cargo +nightly install nu

You can also install Nu with all the bells and whistles (be sure to have installed the dependencies for your platform):

cargo +nightly install nu --all-features

Docker

If you want to pull a pre-built container, you can browse tags for the nushell organization on Quay.io. Pulling a container would come down to:

$ 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 in the container and all dependencies.

Optionally, you can also build the containers locally using the dockerfiles provided: To build the base image:

$ docker build -f docker/Dockerfile.nu-base -t nushell/nu-base .

And then to build the smaller container (using a Multistage build):

$ docker build -f docker/Dockerfile -t nushell/nu .

Either way, you can run either container as follows:

$ 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

Fedora

COPR repo: sudo dnf copr enable atim/nushell -y && sudo dnf install nushell -y

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

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. Just as the Unix philosophy, Nu allows commands to output from stdout and read from stdin. Additionally, commands can output structured data (you can think of this as a third kind of stream). 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 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
━━━━┷━━━━━━━━━━━┷━━━━━━━━━━━┷━━━━━━━━━━┷━━━━━━━━┷━━━━━━━━━━━━━━┷━━━━━━━━━━━━━━━━

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

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.

/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
━━━┷━━━━━━━┷━━━━━━━━━━━━━━━━━┷━━━━━━━━━━┷━━━━━━━━━━

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]
━━━━━━━━━━━━━━━━━━┷━━━━━━━━━━━━━━━━┷━━━━━━━━━━━━━━━━━━

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    │ ISC     │ nu   │ 0.3.0
━━━━━━━━━━━━━━━━━┷━━━━━━━━━━━━━━━━━━━━━━━━━━━━┷━━━━━━━━━┷━━━━━━━━━┷━━━━━━┷━━━━━━━━━

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
0.3.0

Here we use the variable $it to refer to the value being piped to the external command.

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.

To do so, use the enter command, which will allow you create a new "shell" and enter it at the specified path. You can toggle between this new shell and the original shell with the p (for previous) and n (for next), allowing you to navigate around a ring buffer of shells. Once you're done with a shell, you can exit it and remove it from the ring buffer.

Finally, to get a list of all the current shells, you can use the shells command.

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.

There are a few examples in the plugins directory.

Plugins are binaries that are available in your path and follow a "nu_plugin_*" naming convention. These binaries interact with nu via a simple JSON-RPC protocol where the command identifies itself and passes along its configuration, which then makes it available for use. 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

Nu adheres closely to a set of goals that make up its design philosophy. As features are added, they are checked against these goals.

• First and foremost, Nu is cross-platform. Commands and techniques should carry between platforms and offer first-class consistent support for Windows, macOS, and Linux.

• Nu ensures direct compatibility with existing platform-specific executables that make up people's workflows.

• Nu's workflow and tools should have the usability in day-to-day experience of using a shell in 2019 (and beyond).

• Nu views data as both structured and unstructured. It is a structured shell like PowerShell.

• Finally, Nu views data functionally. Rather than using mutation, pipelines act as a means to load, change, and save data without mutable state.

Commands

Initial commands

command	description
cd path	Change to a new path
cp source path	Copy files
date (--utc)	Get the current datetime
fetch url	Fetch contents from a url and retrieve data as a table if possible
help	Display help information about commands
ls (path)	View the contents of the current or given path
mkdir path	Make directories, creates intermediary directories as required.
mv source target	Move files or directories.
open filename	Load a file into a cell, convert to table if possible (avoid by appending '--raw')
post url body (--user ) (--password )	Post content to a url and retrieve data as a table if possible
ps	View current processes
sys	View information about the current system
which filename	Finds a program file.
rm {file or directory}	Remove a file, (for removing directory append '--recursive')
version	Display Nu version

Shell commands

command	description
exit (--now)	Exit the current shell (or all shells)
enter (path)	Create a new shell and begin at this path
p	Go to previous shell
n	Go to next shell
shells	Display the list of current shells

Filters on tables (structured data)

command	description
add column-or-column-path value	Add a new column to the table
edit column-or-column-path value	Edit an existing column to have a new value
embed column	Creates a new table of one column with the given name, and places the current table inside of it
first amount	Show only the first number of rows
get column-or-column-path	Open column and get data from the corresponding cells
inc (column-or-column-path)	Increment a value or version. Optionally use the column of a table
last amount	Show only the last number of rows
nth row-number	Return only the selected row
pick ...columns	Down-select table to only these columns
pivot --header-row	Pivot the tables, making columns into rows and vice versa
reject ...columns	Remove the given columns from the table
reverse	Reverses the table.
skip amount	Skip a number of rows
skip-while condition	Skips rows while the condition matches.
sort-by ...columns	Sort by the given columns
str (column)	Apply string function. Optionally use the column of a table
sum	Sum a column of values
tags	Read the tags (metadata) for values
to-bson	Convert table into .bson binary data
to-csv	Convert table into .csv text
to-json	Convert table into .json text
to-sqlite	Convert table to sqlite .db binary data
to-toml	Convert table into .toml text
to-tsv	Convert table into .tsv text
to-url	Convert table to a urlencoded string
to-yaml	Convert table into .yaml text
where condition	Filter table to match the condition

Filters on text (unstructured data)

command	description
from-bson	Parse binary data as .bson and create table
from-csv	Parse text as .csv and create table
from-ini	Parse text as .ini and create table
from-json	Parse text as .json and create table
from-sqlite	Parse binary data as sqlite .db and create table
from-ssv	Parse text as whitespace-separated values and create table
from-toml	Parse text as .toml and create table
from-tsv	Parse text as .tsv and create table
from-url	Parse urlencoded string and create a table
from-xml	Parse text as .xml and create a table
from-yaml	Parse text as a .yaml/.yml and create a table
lines	Split single string into rows, one per line
size	Gather word count statistics on the text
split-column sep ...column-names	Split row contents across multiple columns via the separator, optionally give the columns names
split-row sep	Split row contents over multiple rows via the separator
trim	Trim leading and following whitespace from text data
{external-command} $it	Run external command with given arguments, replacing $it with each row text

Consuming commands

command	description
autoview	View the contents of the pipeline as a table or list
binaryview	Autoview of binary data (optional feature)
clip	Copy the contents of the pipeline to the copy/paste buffer (optional feature)
save filename	Save the contents of the pipeline to a file
table	View the contents of the pipeline as a table
textview	Autoview of text data
tree	View the contents of the pipeline as a tree (optional feature)

License

The project is made available under the MIT license. See "LICENSE" for more information.