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kitten-diff(1) kitty kitten-diff(1)

Name

kitten-diff - Pretty, side-by-side diffing of files and images

A fast side-by-side diff tool with syntax highlighting and images

Major features

  • Displays diffs side-by-side in the kitty terminal
  • Does syntax highlighting of the displayed diffs, asynchronously, for maximum speed
  • Displays images as well as text diffs, even over SSH
  • Does recursive directory diffing

Screenshot, showing a sample diff (images not supported)


Installation

Simply install kitty.

Usage

In the kitty terminal, run:

kitten diff file1 file2


to see the diff between file1 and file2.

Create an alias in your shell's startup file to shorten the command, for example:

alias d="kitten diff"


Now all you need to do to diff two files is:

d file1 file2


You can also pass directories instead of files to see the recursive diff of the directory contents.

Keyboard controls

Action Shortcut
Quit Q, Esc
Scroll line up K, Up
Scroll line down J, Down
Scroll page up PgUp
Scroll page down PgDn
Scroll to top Home
Scroll to bottom End
Scroll to next page Space, PgDn
Scroll to previous page PgUp
Scroll to next change N
Scroll to previous change P
Increase lines of context +
Decrease lines of context -
All lines of context A
Restore default context =
Search forwards /
Search backwards ?
Clear search Esc
Scroll to next match >, .
Scroll to previous match <, ,
Copy selection to clipboard y
Copy selection or exit Ctrl+C

Integrating with git

Add the following to ~/.gitconfig:

[diff]

tool = kitty
guitool = kitty.gui [difftool]
prompt = false
trustExitCode = true [difftool "kitty"]
cmd = kitten diff $LOCAL $REMOTE [difftool "kitty.gui"]
cmd = kitten diff $LOCAL $REMOTE


Now to use kitty-diff to view git diffs, you can simply do:

git difftool --no-symlinks --dir-diff


Once again, creating an alias for this command is useful.

Why does this work only in kitty?

The diff kitten makes use of various features that are kitty only, such as the kitty graphics protocol, the extended keyboard protocol, etc. It also leverages terminal program infrastructure I created for all of kitty's other kittens to reduce the amount of code needed (the entire implementation is under 3000 lines of code).

And fundamentally, it's kitty only because I wrote it for myself, and I am highly unlikely to use any other terminals :)

Configuration

You can configure the colors used, keyboard shortcuts, the diff implementation, the default lines of context, etc. by creating a diff.conf file in your kitty config folder. See below for the supported configuration directives.

Diffing


syntax_aliases pyj:py pyi:py recipe:py


File extension aliases for syntax highlight. For example, to syntax highlight file.xyz as file.abc use a setting of xyz:abc. Multiple aliases must be separated by spaces.


num_context_lines 3


The number of lines of context to show around each change.


diff_cmd auto


The diff command to use. Must contain the placeholder _CONTEXT_ which will be replaced by the number of lines of context. A few special values are allowed: auto will automatically pick an available diff implementation. builtin will use the anchored diff algorithm from the Go standard library. git will use the git command to do the diffing. diff will use the diff command to do the diffing.


replace_tab_by \x20\x20\x20\x20


The string to replace tabs with. Default is to use four spaces.


A glob pattern that is matched against only the filename of files and directories. Matching files and directories are ignored when scanning the filesystem to look for files to diff. Can be specified multiple times to use multiple patterns. For example:

ignore_name .git
ignore_name *~
ignore_name *.pyc


Colors


pygments_style default


The pygments color scheme to use for syntax highlighting. See pygments builtin styles for a list of schemes. Note that this does not change the colors used for diffing, only the colors used for syntax highlighting. To change the general colors use the settings below.


foreground black
background white


Basic colors


title_fg black
title_bg white


Title colors


margin_bg #fafbfc
margin_fg #aaaaaa


Margin colors


removed_bg           #ffeef0
highlight_removed_bg #fdb8c0
removed_margin_bg    #ffdce0


Removed text backgrounds


added_bg           #e6ffed
highlight_added_bg #acf2bd
added_margin_bg    #cdffd8


Added text backgrounds


filler_bg #fafbfc


Filler (empty) line background


margin_filler_bg none


Filler (empty) line background in margins, defaults to the filler background


hunk_margin_bg #dbedff
hunk_bg        #f1f8ff


Hunk header colors


search_bg #444
search_fg white
select_bg #b4d5fe
select_fg black


Highlighting

Keyboard shortcuts


map q quit
map esc quit



map j scroll_by 1
map down scroll_by 1



map k scroll_by -1
map up scroll_by -1



map home scroll_to start



map end scroll_to end



map page_down scroll_to next-page
map space scroll_to next-page



map page_up scroll_to prev-page



map n scroll_to next-change



map p scroll_to prev-change



map a change_context all



map = change_context default



map + change_context 5



map - change_context -5



map / start_search regex forward



map ? start_search regex backward



map . scroll_to next-match
map > scroll_to next-match



map , scroll_to prev-match
map < scroll_to prev-match



map f start_search substring forward



map b start_search substring backward



map y copy_to_clipboard



map ctrl+c copy_to_clipboard_or_exit


Source code for diff

The source code for this kitten is available on GitHub.

Command line interface

kitty +kitten diff [options] file_or_directory_left file_or_directory_right


Show a side-by-side diff of the specified files/directories. You can also use ssh:hostname:remote-file-path to diff remote files.

Options

Number of lines of context to show between changes. Negative values use the number set in diff.conf. Default: -1

Specify a path to the configuration file(s) to use. All configuration files are merged onto the builtin diff.conf, overriding the builtin values. This option can be specified multiple times to read multiple configuration files in sequence, which are merged. Use the special value NONE to not load any config file.

If this option is not specified, config files are searched for in the order: $XDG_CONFIG_HOME/kitty/diff.conf, ~/.config/kitty/diff.conf, $XDG_CONFIG_DIRS/kitty/diff.conf. The first one that exists is used as the config file.

If the environment variable KITTY_CONFIG_DIRECTORY is specified, that directory is always used and the above searching does not happen.

If /etc/xdg/kitty/diff.conf exists, it is merged before (i.e. with lower priority) than any user config files. It can be used to specify system-wide defaults for all users. You can use either - or /dev/stdin to read the config from STDIN.


Override individual configuration options, can be specified multiple times. Syntax: name=value. For example: -o background=gray

Sample diff.conf

You can download a sample diff.conf file with all default settings and comments describing each setting by clicking: sample diff.conf.

Author

Kovid Goyal

Copyright

2023, Kovid Goyal

December 25, 2023 0.31.0