delta/README.md

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## A syntax-highlighting pager 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/52205/65245123-e8392000-dae3-11e9-88ef-fcccf6ade952.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/0.0.15/delta-0.0.15-x86_64-unknown-linux-musl.tar.gz) | [MacOS](https://github.com/dandavison/delta/releases/download/0.0.15/delta-0.0.15-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
```

#### 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"
```

#### 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 add new languages/color themes to delta, the process is

1. Clone the delta repo
2. Create new versions of the files `assets/syntaxes.bin` and/or `assets/themes.bin`. Please see the [bat](https://github.com/sharkdp/bat#adding-new-syntaxes--language-definitions) documentation for instructions on how to create new versions of these files. You will need to copy them into the `assets/` directory of the delta git repo after creating them.
3. Recompile delta: `cargo build --release`
4. Now you have a new delta executable at `target/release/delta` that should feature your new language/theme (use `--list-languages` / `--list-themes` to check).

Delta does not currently support reading these files dynamically from `~/.config` as `bat` does, but this is a feature that could be added.


## 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:
        --compare-themes            Compare available syntax highlighting themes. To use this option, supply git diff
                                    output to delta on standard input. For example: `git show --color=always | delta
                                    --compare-themes`.
        --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-themes               List available syntax highlighting 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=]
    -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