delta/README.md

[![Build Status](https://travis-ci.com/dandavison/delta.svg?branch=master)](https://travis-ci.com/dandavison/delta)

## A syntax-highlighter for git and diff output

Delta brings language syntax highlighting, within-line insertion/deletion detection, and restructured diff output to git on the command line. Here's an example of `git show` output with git configured to use delta as its pager:

<img width=800px src="https://user-images.githubusercontent.com/52205/74090846-f200f700-4a75-11ea-9427-89e1fa686bfe.png" alt="image" />


## Features
|                                                | delta | git | diff-so-fancy | github/gitlab |
|------------------------------------------------|-------|-----|---------------|---------------|
| language syntax highlighting                   | ✅    | ❌  | ❌            | ✅             |
| within-line insertion/deletion detection       | ✅    | ❌  | ✅            | ✅             |
| multiple insertion/deletions detected per line | ✅    | ❌  | ❌            | ✅             |
| matching of unequal numbers of changed lines   | ✅    | ❌  | ❌            | ❌             |

In addition, delta handles traditional unified diff output.

## Installation

Executables: [Linux](https://github.com/dandavison/delta/releases/download/0.0.16/delta-0.0.16-x86_64-unknown-linux-musl.tar.gz) | [MacOS](https://github.com/dandavison/delta/releases/download/0.0.16/delta-0.0.16-x86_64-apple-darwin.tar.gz) | [Windows](https://github.com/dandavison/delta/releases/download/0.0.15/delta-0.0.15-x86_64-pc-windows-msvc.zip) | [All](https://github.com/dandavison/delta/releases)

Homebrew:
```sh
brew install git-delta
```

FreeBSD pkg(8):
```sh
pkg install git-delta
```

Archlinux (AUR):
```sh
# With AUR helper `yay`:
yay -S git-delta

# Alternatively, without an AUR helper:
git clone https://aur.archlinux.org/git-delta.git
cd git-delta
makepkg -csri
```

#### Configure git to use delta

```sh
git config --global core.pager "delta --dark"  # --light for light terminal backgrounds
```

Alternatively, you can edit your `.gitconfig` directly. Delta accepts many command line options to alter colors and other details of the output. An example is
```
[core]
    pager = delta --dark --plus-color="#012800" --minus-color="#340001" --theme="base16-ocean.dark"
```

#### Configure mercurial to use delta

Edit your `.hgrc` as follow and set the options you want for delta in it:
```
[pager]
pager = delta --dark
```

#### Windows

`less.exe` installed with git doesn't work well with `delta`. A patched version of `less.exe` and instructions for installing can be found [here](https://github.com/lzybkr/less/releases/tag/fix_windows_vt).

All git commands that display diff output should now display syntax-highlighted output. For example:
  - `git diff`
  - `git show`
  - `git log -p`
  - `git stash show -p`
  - `git reflog -p`

Delta also handles unified diff output:
```
diff -u a.txt b.txt | delta
```

<br>


<br>

<table>
  <tr>
    <td>
      delta --dark (default)
    </td>
    <td>
      delta --light
    </td>
  </tr>
  <tr>
    <td>
      <img width=500px style="border: 1px solid black"
           src="https://user-images.githubusercontent.com/52205/65245970-85488880-dae5-11e9-9fd2-d358071bcf7f.png"
           alt="image" />
    </td>
    <td>
      <img width=500px style="border: 1px solid black"
           src="https://user-images.githubusercontent.com/52205/65246093-c93b8d80-dae5-11e9-8346-eb8bc0a89e75.png"
           alt="image" />
    </td>
  </tr>
</table>

<br>


## Supported languages and themes
To list the supported languages and color themes, use `delta --list-languages` and `delta --list-theme-names`. To see a demo of the color themes, use `delta --list-themes`.

delta uses the same mechanisms as [bat](https://github.com/sharkdp/bat#adding-new-syntaxes--language-definitions) for locally adding custom color themes and support for new languages: please see the [bat](https://github.com/sharkdp/bat#adding-new-syntaxes--language-definitions) documentation. You will need to install bat in order to run the `bat cache --build` command.

The languages and color themes that ship with delta are those that ship with bat. So, to propose a new language or color theme for inclusion in delta, it would need to be a helpful addition to bat, in which case please open a PR against bat.


## 24 bit color

Delta works best if your terminal application supports 24 bit colors. See https://gist.github.com/XVilka/8346728. For example, on MacOS, iTerm2 works but Terminal.app does not.

If you're using tmux, it's worth checking that 24 bit color is  working correctly. For example, run a color test script like [this  one](https://gist.githubusercontent.com/lifepillar/09a44b8cf0f9397465614e622979107f/raw/24-bit-color.sh),  or one of the others listed [here](https://gist.github.com/XVilka/8346728). If  you do not see smooth color gradients, see the discussion at  [tmux#696](https://github.com/tmux/tmux/issues/696). The short  version is you need something like this in your `~/.tmux.conf`:
```
set -ga terminal-overrides ",xterm-256color:Tc"
```
and you may then  need to quit tmux completely for it to take effect.

<br>

## Mouse scrolling

If mouse scrolling is broken, try setting your `BAT_PAGER` environment variable to (at least) `less -R` .
See [issue #58](https://github.com/dandavison/delta/issues/58) and [bat README / "Using a different pager"](https://github.com/sharkdp/bat#using-a-different-pager).

## Options
Here's the output of `delta --help`. To use these options, add them to the delta command line in your `.gitconfig` file.

```
USAGE:
    delta [FLAGS] [OPTIONS]

FLAGS:
        --dark                      Use colors appropriate for a dark terminal background.  For more control, see
                                    --theme, --plus-color, and --minus-color.
    -h, --help                      Prints help information
        --highlight-removed         Apply syntax highlighting to removed lines. The default is to apply syntax
                                    highlighting to unchanged and new lines only.
        --light                     Use colors appropriate for a light terminal background. For more control, see
                                    --theme, --plus-color, and --minus-color.
        --list-languages            List supported languages and associated file extensions.
        --list-theme-names          List available syntax-highlighting color themes.
        --list-themes               List available syntax highlighting themes, each with an example of highlighted diff
                                    output. If diff output is supplied on standard input then this will be used for the
                                    demo. For example: `git show --color=always | delta --list-themes`.
        --show-background-colors    Show the command-line arguments (RGB hex codes) for the background colors that are
                                    in effect. The hex codes are displayed with their associated background color. This
                                    option can be combined with --light and --dark to view the background colors for
                                    those modes. It can also be used to experiment with different RGB hex codes by
                                    combining this option with --minus-color, --minus-emph-color, --plus-color, --plus-
                                    emph-color.
    -V, --version                   Prints version information

OPTIONS:
        --commit-style <commit_style>
            Formatting style for commit section of git output. Options are: plain, box. [default: plain]

        --file-style <file_style>
            Formatting style for file section of git output. Options are: plain, box, underline. [default: underline]

        --hunk-style <hunk_style>
            Formatting style for hunk section of git output. Options are: plain, box. [default: box]

        --max-line-distance <max_line_distance>
            The maximum distance between two lines for them to be inferred to be homologous. Homologous line pairs are
            highlighted according to the deletion and insertion operations transforming one into the other. [default:
            0.3]
        --minus-color <minus_color>                The background color (RGB hex) to use for removed lines.
        --minus-emph-color <minus_emph_color>
            The background color (RGB hex) to use for emphasized sections of removed lines.

        --plus-color <plus_color>                  The background color (RGB hex) to use for added lines.
        --plus-emph-color <plus_emph_color>
            The background color (RGB hex) to use for emphasized sections of added lines.

        --tabs <tab_width>
            The number of spaces to replace tab characters with. Use --tabs=0 to pass tab characters through directly,
            but note that in that case delta will calculate line widths assuming tabs occupy one character's width on
            the screen: if your terminal renders tabs as more than than one character wide then delta's output will look
            incorrect. [default: 4]
        --theme <theme>
            The syntax highlighting theme to use. Use --theme=none to disable syntax highlighting. If the theme is not
            set using this option, it will be taken from the BAT_THEME environment variable, if that contains a valid
            theme name. Use --list-themes and --compare-themes to view available themes. [env: BAT_THEME=GitHub]
    -w, --width <width>
            The width (in characters) of the background color highlighting. By default, the width is the current
            terminal width. Use --width=variable to apply background colors to the end of each line, without right
            padding to equal width.
```

<br>


## Comparisons

<table>
  <tr>
    <td>
      delta vs. git
    </td>
    <td>
      <img width=500px style="border: 1px solid black"
           src="https://user-images.githubusercontent.com/52205/65248525-32250480-daea-11e9-9965-1a05c6a4bdf4.png"
           alt="image" />
    </td>
    <td>
      <img width=500px style="border: 1px solid black"
           src="https://user-images.githubusercontent.com/52205/65248441-14f03600-daea-11e9-88a1-d96bbb6947f8.png"
           alt="image" />
    </td>
  </tr>
  <tr>
    <td>
      delta vs. diff-so-fancy
    </td>
    <td>
      <img width=500px style="border: 1px solid black"
           src="https://user-images.githubusercontent.com/52205/65248525-32250480-daea-11e9-9965-1a05c6a4bdf4.png"
           alt="image" />
    </td>
    <td>
      <img width=500px style="border: 1px solid black"
           src="https://user-images.githubusercontent.com/52205/65248407-07d34700-daea-11e9-9a8f-6d81f4021abf.png"
           alt="image" />
    </td>
  </tr>
  <tr>
    <td>
      delta vs. github
    </td>
    <td>
      <img width=500px style="border: 1px solid black"
           src="https://user-images.githubusercontent.com/52205/65248525-32250480-daea-11e9-9965-1a05c6a4bdf4.png"
           alt="image" />
    </td>
    <td>
      <img width=500px style="border: 1px solid black"
           src="https://user-images.githubusercontent.com/52205/65248749-9a73e600-daea-11e9-9c0d-29c8f1dea08e.png"
           alt="image" />
    </td>
  </tr>
</table>





## Credit
  https://github.com/trishume/syntect<br>
  https://github.com/sharkdp/bat<br>
  https://github.com/so-fancy/diff-so-fancy