bat/README.md

<p align="center">
  <img src="doc/logo-header.svg" alt="bat - a cat clone with wings"><br>
  <a href="https://travis-ci.org/sharkdp/bat"><img src="https://travis-ci.org/sharkdp/bat.svg?branch=master" alt="Build Status"></a>
  <a href="https://ci.appveyor.com/project/sharkdp/bat"><img src="https://ci.appveyor.com/api/projects/status/cptsmtbiwbnr2vhf?svg=true"></a>
  <img src="https://img.shields.io/crates/l/bat.svg" alt="license">
  <a href="https://crates.io/crates/bat"><img src="https://img.shields.io/crates/v/bat.svg?colorB=319e8c" alt="Version info"></a><br>
  A <i>cat(1)</i> clone with syntax highlighting and Git integration.
</p>

<p align="center">
  <a href="#syntax-highlighting">Key Features</a> •
  <a href="#how-to-use">How To Use</a> •
  <a href="#installation">Installation</a> •
  <a href="#customization">Customization</a> •
  <a href="#project-goals-and-alternatives">Project goals, alternatives</a>
</p>

### Syntax highlighting

`bat` supports syntax highlighting for a large number of programming and markup
languages:

![Syntax highlighting example](https://imgur.com/rGsdnDe.png)

### Git integration

`bat` communicates with `git` to show modifications with respect to the index
(see left side bar):

![Git integration example](https://i.imgur.com/2lSW4RE.png)

### Automatic paging

`bat` can pipe its own output to `less` if the output is too large for one screen.

### File concatenation

Oh.. you can also use it to concatenate files :wink:. Whenever
`bat` detects a non-interactive terminal, it will fall back to printing
the plain file contents.

## How to use

Display a single file on the terminal

```bash
> bat README.md
```

Display multiple files at once

```bash
> bat src/*.rs
```

Read from stdin, explicitly specify the language

```bash
> yaml2json .travis.yml | json_pp | bat -l json
```

```bash
> curl -s https://raw.githubusercontent.com/sharkdp/bat/master/src/main.rs | bat -l rs
```

As a replacement for `cat`:

```bash
bat > note.md  # quickly create a new file

bat header.md content.md footer.md > document.md

bat -n main.rs  # show line numbers (only)

bat f - g  # output 'f', then stdin, then 'g'.
```

## Installation

### On Ubuntu
*... and other Debian-based Linux distributions.*

Download the latest `.deb` package from the [release page](https://github.com/sharkdp/bat/releases)
and install it via:
``` bash
sudo dpkg -i bat_0.7.1_amd64.deb  # adapt version number and architecture
```

### On Arch Linux

You can install [the `bat` package](https://www.archlinux.org/packages/community/x86_64/bat/)
from the official sources:

```bash
pacman -S bat
```

### On Void Linux

You can install `bat` via xbps-install:
```
xbps-install -S bat
```

### On FreeBSD

You can install a precompiled [`bat` package](https://www.freshports.org/textproc/bat) with pkg:

```bash
pkg install bat
```

or build it on your own from the FreeBSD ports:

```bash
cd /usr/ports/textproc/bat
make install
```

### Via Ansible

You can install `bat` with [Ansible](https://www.ansible.com/):

```bash
# Install role on local machine
ansible-galaxy install aeimer.install_bat
```

```yaml
---
# Playbook to install bat
- host: all
  roles:
    - aeimer.install_bat
```

- [Ansible Galaxy](https://galaxy.ansible.com/aeimer/install_bat)
- [GitHub](https://github.com/aeimer/ansible-install-bat)

This should work with the following distributions:
- Debian/Ubuntu
- ARM (eg. Raspberry PI)
- Arch Linux
- Void Linux
- FreeBSD
- MacOS

### On macOS

You can install `bat` with [Homebrew](http://braumeister.org/formula/bat):

```bash
brew install bat
```

### On Windows

You can download prebuilt binaries from the [Release page](https://github.com/sharkdp/bat/releases),
or install it with [scoop](https://scoop.sh/):

```bash
scoop install bat
```

[See below](#using-bat-on-windows) for notes.

### From binaries

Check out the [Release page](https://github.com/sharkdp/bat/releases) for
prebuilt versions of `bat` for many different architectures.

### From source

If you want to build `bat` from source, you need Rust 1.26 or
higher. You can then use `cargo` to build everything:

```bash
cargo install bat
```

You may have to install `cmake` and the `libz` development package
(`libz-dev` or `libz-devel`) in order for the build to succeed.

## Customization

### Highlighting theme

Use `bat --list-themes` to get a list of all available themes for syntax
highlighting. To select the `TwoDark` theme, call `bat` with the
`--theme=TwoDark` option or set the `BAT_THEME` environment variable to
`TwoDark`. Use `export BAT_THEME="TwoDark"` in your shell's startup file to
make the change permanent.

### Output style

You can use the `--style` option to control the appearance of `bat`s output.
You can use `--style=numbers,changes`, for example, to show only Git changes
and line numbers but no grid and no file header. Use the `BAT_STYLE` environment
variable to make these changes permanent.

### Adding new syntaxes / language definitions

`bat` uses the excellent [`syntect`](https://github.com/trishume/syntect/)
library for syntax highlighting. `syntect` can read any
[Sublime Text `.sublime-syntax` file](https://www.sublimetext.com/docs/3/syntax.html)
and theme. To add new syntax definitions, do the following.

Create a folder with syntax definition files:

```bash
BAT_CONFIG_DIR="$(bat cache --config-dir)"

mkdir -p "$BAT_CONFIG_DIR/syntaxes"
cd "$BAT_CONFIG_DIR/syntaxes"

# Put new '.sublime-syntax' language definition files
# in this folder (or its subdirectories), for example:
git clone https://github.com/tellnobody1/sublime-purescript-syntax
```

Now use the following command to parse these files into a binary cache:

```bash
bat cache --init
```

Finally, use `bat --list-languages` to check if the new languages are available.

If you ever want to go back to the default settings, call:

```bash
bat cache --clear
```

### Adding new themes

This works very similar to how we add new syntax definitions.

First, create a folder with the new syntax highlighting themes:
```bash
BAT_CONFIG_DIR="$(bat cache --config-dir)"

mkdir -p "$BAT_CONFIG_DIR/themes"
cd "$BAT_CONFIG_DIR/themes"

# Download a theme in '.tmTheme' format, for example:
git clone https://github.com/greggb/sublime-snazzy

# Update the binary cache
bat cache --init
```

Finally, use `bat --list-themes` to check if the new themes are available.

### Using a different pager

`bat` uses the pager that is specified in the `PAGER` environment variable. If this variable is not
set, `less` is used by default. If you want to use a different pager, you can either modify the
`PAGER` variable or set the `BAT_PAGER` environment variable to override what is specified in
`PAGER`. If you want to pass command-line arguments to the pager, you need to create a small shell
script as a wrapper, for example:

```bash
#!/bin/bash

less --tabs 4 -RF "$@"
```

## Using `bat` on Windows

`bat` mostly works out-of-the-box on Windows, but a few features may need extra configuration.

### Paging

Windows only includes a very limited pager in the form of `more`. You can download a Windows binary
for `less` [from its homepage](http://www.greenwoodsoftware.com/less/download.html) or [through
Chocolatey](https://chocolatey.org/packages/Less). To use it, place the binary in a directory in
your `PATH` or [define an environment variable](#using-a-different-pager).

### Colours

Windows 10 natively supports colours in both `conhost.exe` (Command Prompt) and PowerShell since
[v1511](https://en.wikipedia.org/wiki/Windows_10_version_history#Version_1511_(November_Update)), as
well as in newer versions of bash. On earlier versions of Windows, you can use
[Cmder](http://cmder.net/), which includes [ConEmu](https://conemu.github.io/).

**Note:** The Git and MSYS versions of `less` do not correctly interpret colours on Windows. If you
don’t have any other pagers installed, you can disable paging entirely by passing `--paging=never`
or by setting `BAT_PAGER` to an empty string.

### Cygwin

`bat` on Windows does not natively support Cygwin's unix-style paths (`/cygdrive/*`). When passed an absolute cygwin path as an argument, `bat` will encounter the following error: `The system cannot find the path specified. (os error 3)` 

This can be solved by creating a wrapper or adding the following function to your `.bash_profile` file:

```shell
bat() {
    local index
    local args=("$@")
    for index in $(seq 0 ${#args[@]}) ; do
        case "${args[index]}" in
        -*) continue;;
        *)  [ -e "${args[index]}" ] && args[index]="$(cygpath --windows "${args[index]}")";;
        esac
    done
    command bat "${args[@]}"
}
```

## Troubleshooting

### Terminals & colors

`bat` handles terminals *with* and *without* truecolor support. However, the colors in the syntax
highlighting themes are not optimized for 8-bit colors and it is therefore strongly recommended
that you use a terminal with 24-bit truecolor support (`terminator`, `konsole`, `iTerm2`, ...).
See [this article](https://gist.github.com/XVilka/8346728) for more details and a full list of
terminals with truecolor support.

Make sure that your truecolor terminal sets the `COLORTERM` variable to either `truecolor` or
`24bit`. Otherwise, `bat` will not be able to determine whether or not 24-bit escape sequences
are supported (and fall back to 8-bit colors).

### Line numbers and grid are hardly visible

Please try a different theme (see `bat --list-themes` for a list). The `OneHalfDark` and
`OneHalfLight` themes provide grid and line colors that are brighter.

## Development

```bash
# Recursive clone to retrieve all submodules
git clone --recursive https://github.com/sharkdp/bat

# Build (debug version)
cd bat
cargo build

# Run unit tests and integration tests
cargo test

# Install (release version)
cargo install

# Build a bat binary with modified syntaxes and themes
bash assets/create.sh
cargo install -f
```

## Project goals and alternatives

`bat` tries to achieve the following goals:

- Provide beautiful, advanced syntax highlighting
- Integrate with Git to show file modifications
- Be a drop-in replacement for (POSIX) `cat`
- Offer a user-friendly command-line interface

There are a lot of alternatives, if you are looking for similar programs. See
[this document](doc/alternatives.md) for a comparison.