mawww's experiment for a better code editor
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TL;DR

Modal editor — Faster as in fewer keystrokes — Multiple selections — Orthogonal design

git clone http://github.com/mawww/kakoune.git
cd kakoune/src
make
./kak

See http://github.com/mawww/golf for kakoune solutions to vimgolf challenges, regularly beating the best Vim solution.

See the design document for more information on Kakoune philosophy and design.

1. Introduction

Kakoune is a code editor that implements Vi’s "keystrokes as a text editing language" model. As it’s also a modal editor, it is somewhat similar to the Vim editor (after which Kakoune was originally inspired).

Kakoune can operate in two modes, normal and insertion. In insertion mode, keys are directly inserted into the current buffer. In normal mode, keys are used to manipulate the current selection and to enter insertion mode.

Kakoune has a strong focus on interactivity, most commands provide immediate and incremental results, while still being competitive (as in keystroke count) with Vim.

Kakoune works on selections, which are oriented, inclusive range of characters, selections have an anchor and a cursor character. Most commands move both of them, except when extending selection where the anchor character stays fixed and the cursor one moves around.

Join us on freenode IRC #Kakoune

1.1. Features

  • Multiple selections as a central way of interacting

  • Powerful selection manipulation primitives

    • Select all regex matches in current selections

    • Keep selections containing/not containing a match for a given regex

    • Split current selections with a regex

    • Text objects (paragraph, sentence, nestable blocks)

  • Powerful text manipulation primitives

    • Align selections

    • Rotate selection contents

    • Case manipulation

    • Indentation

    • Piping each selection to external filter

  • Client-Server architecture

    • Multiple clients on the same editing session

    • Use tmux or your X11 window manager to manage windows

  • Simple interaction with external programs

  • Automatic contextual help

  • Automatic as you type completion

  • Macros

  • Hooks

  • Syntax Highlighting

    • Supports multiple languages in the same buffer

    • Highlight a buffer differently in different windows

1.2. Screenshots

Kakoune in i3
Figure 1. Kakoune in i3
Kakoune in tmux
Figure 2. Kakoune in tmux

2. Getting started

2.1. Building

Kakoune dependencies are:

  • A C++14 compliant compiler (GCC >= 5 or clang >= 3.9) along with its associated C++ standard library (libstdc++ or libc++)

  • ncurses with wide-characters support (>= 5.3, generally referred to as libncursesw)

  • asciidoc (for the a2k tool), to generate man pages

To build, just type make in the src directory. To generate man pages, type make man in the src directory.

Kakoune can be built on Linux, MacOS, and Cygwin. Due to Kakoune relying heavily on being in a Unix-like environment, no native Windows version is planned.

2.2. Installing

In order to install kak on your system, rather than running it directly from its source directory, type make install, you can specify the PREFIX and DESTDIR if needed.

Tip
Homebrew (macOS) or Linuxbrew
brew install kakoune
Tip
Fedora supported versions and Rawhide

Use the copr repository.

dnf copr enable jkonecny/kakoune
dnf install kakoune
Tip
Arch Linux

Kakoune is found in the repositories.

pacman -S kakoune
Tip
Gentoo

Kakoune is found in portage as app-editors/kakoune

Tip
Exherbo
cave resolve -x repository/mawww
cave resolve -x kakoune
Tip
openSUSE

kakoune can be found in the editors devel project. Make sure to adjust the link below to point to the repository of your openSUSE version.

#Example for Tumbleweed:
sudo zypper addrepo http://download.opensuse.org/repositories/editors/openSUSE_Factory/editors.repo
sudo zypper refresh
sudo zypper install kakoune
Tip
Ubuntu

Building on Ubuntu 16.04. Make sure you have .local/bin in your path to make the kak binary available from your shell.

sudo apt install libncursesw5-dev asciidoc
git clone https://github.com/mawww/kakoune.git && cd kakoune/src
make
PREFIX=$HOME/.local make install
Tip
FreeBSD

Kakoune is available in the official ports tree as editors/kakoune.

A binary package is also available and can be installed with

pkg install kakoune
Tip
Solus

Kakoune is available in the Solus stable repository.

It can be installed with

eopkg install kakoune
Tip
Void

Kakoune is available in the repositories.

It can be installed with

xbps-install -S kakoune
Tip
Termux

Kakoune is available in the repositories.

It can be installed with

pkg install kakoune

2.3. Running

Just running kak launch a new kak session with a client on local terminal. Run kak -help to discover the valid command line flags.

2.3.1. Configuration

There are two directories containing Kakoune’s scripts:

  • runtime: located in ../share/kak/ relative to the kak binary contains the system scripts, installed with Kakoune.

  • userconf: located in $XDG_CONFIG_HOME/kak/, which will fallback to $HOME/.config/kak/ if $XDG_CONFIG_HOME is not set, containing the user configuration.

Unless -n is specified, Kakoune will load its startup script located at ${runtime}/kakrc relative to the kak binary. This startup script is responsible for loading the user configuration.

First, Kakoune will search recursively for .kak files in the autoload directory. It will first look for an autoload directory at ${userconf}/autoload and will fallback to ${runtime}/autoload if it does not exist.

Once all those files are loaded, Kakoune will try to source ${runtime}/kakrc.local which is expected to contain distribution provided configuration.

And finally, the user configuration will be loaded from ${userconf}/kakrc.

Note
If you create a user autoload directory in ${userconf}/autoload, the system one at ${runtime}/autoload will not be loaded anymore. You can add a symbolic link to it (or to individual scripts) inside ${userconf}/autoload to keep loading system scripts.

3. Basic Interaction

3.1. Selections

The main concept in Kakoune is the selection. A selection is an inclusive, directed range of character. A selection has two ends, the anchor and the cursor.

There is always at least one selection, and a selection is always at least one character (in which case the anchor and cursor of the selections are on the same character).

3.2. Normal Mode

In normal mode, keys are not inserted directly inside the buffer, but are editing commands. These commands provide ways to manipulate either the selections themselves, or the selected text.

3.3. Insert Mode

When entering insert mode, keys are now directly inserted before each selection’s cursor. Some additional keys are recognised in insert mode:

  • <esc>: leave insert mode

  • <backspace>: delete characters before cursors

  • <del>: delete characters under cursors

  • <left>, <right>, <up>, <down>: move the cursors in given direction

  • <home>: move cursors to line begin

  • <end>: move cursors to end of line

  • <c-n>: select next completion candidate

  • <c-p>: select previous completion candidate

  • <c-x>: explicit insert completion query, followed by:

    • f: explicit file completion

    • w: explicit word completion

    • l: explicit line completion

  • <c-o>: disable automatic completion for this insert session

  • <c-r>: insert contents of the register given by next key

  • <c-v>: insert next keystroke directly into the buffer, without interpreting it.

  • <c-u>: commit changes up to now as a single undo group.

  • <a-;>: escape to normal mode for a single command

3.4. Movement

  • h: select the character on the left of selection end

  • j: select the character below the selection end

  • k: select the character above the selection end

  • l: select the character on the right of selection end

  • w: select the word and following whitespaces on the right of selection end

  • b: select preceding whitespaces and the word on the left of selection end

  • e: select preceding whitespaces and the word on the right of selection end

  • <a-[wbe]>: same as [wbe] but select WORD instead of word

  • f: select to the next occurence of given character

  • t: select until the next occurence of given character

  • <a-[ft]>: same as [ft] but in the other direction

  • m: select to matching character

  • M: extend selection to matching character

  • x: select line on which selection end lies (or next line when end lies on an end-of-line)

  • X: similar to x, except the current selection is extended

  • <a-x>: expand selections to contain full lines (including end-of-lines)

  • <a-X>: trim selections to only contain full lines (not including last end-of-line)

  • %: select whole buffer

  • <a-h>: select to line begin

  • <a-l>: select to line end

  • /: search (select next match)

  • <a-/>: search (select previous match)

  • ?: search (extend to next match)

  • <a-?>: search (extend to previous match)

  • n: select next match

  • N: add a new selection with next match

  • <a-n>: select previous match

  • <a-N>: add a new selection with previous match

  • pageup, <c-b>: scroll one page up

  • pagedown, <c-f>: scroll one page down

  • <c-u>: scroll half a page up

  • <c-d>: scroll half a page down

  • ): rotate selections (the main selection becomes the next one)

  • (: rotate selections backwards

  • ;: reduce selections to their cursor

  • <a-;>: flip the selections' direction

  • <a-:>: ensure selections are in forward direction (cursor after anchor)

  • <a-.>: repeat last object or f/t selection command.

  • _: trim selections

A word is a sequence of alphanumeric characters or underscore, a WORD is a sequence of non whitespace characters.

3.5. Appending

for most selection commands, using shift permits extending current selection instead of replacing it. for example, wWW selects 3 consecutive words

3.6. Using Counts

Most selection commands also support counts, which are entered before the command itself.

For example, 3W selects 3 consecutive words and 3w select the third word on the right of selection end.

3.7. Disabling Hooks

Any normal mode command can be prefixed with \ which will disable hook execution for the duration for the command (including the duration of modes the command could move to, so \i will disable hooks for the whole insert session).

As autoindentation is implemented in terms of hooks, this can be used to disable it when pasting text.

3.8. Changes

  • i: enter insert mode before current selection

  • a: enter insert mode after current selection

  • d: yank and delete current selection

  • c: yank and delete current selection and enter insert mode

  • .: repeat last insert mode change (i, a, or c, including the inserted text)

  • <a-d>: delete current selection

  • <a-c>: delete current selection and enter insert mode

  • I: enter insert mode at current selection begin line start

  • A: enter insert mode at current selection end line end

  • o: enter insert mode in one (or given count) new lines below current selection end

  • O: enter insert mode in one (or given count) new lines above current selection begin

  • <a-o>: add an empty line below cursor

  • <a-O>: add an empty line above cursor

  • y: yank selections

  • p: paste after current selection end

  • P: paste before current selection begin

  • <a-p>: paste all after current selection end, and select each pasted string.

  • <a-P>: paste all before current selection begin, and select each pasted string.

  • R: replace current selection with yanked text

  • <a-R>: replace current selection with every yanked text

  • r: replace each character with the next entered one

  • <a-j>: join selected lines

  • <a-J>: join selected lines and select spaces inserted in place of line breaks

  • <a-m>: merge contiguous selections together (works across lines as well)

  • <gt> (>): indent selected lines

  • <a-gt>: indent selected lines, including empty lines

  • <lt> (<): deindent selected lines

  • <a-lt>: deindent selected lines, do not remove incomplete indent (3 leading spaces when indent is 4)

  • |: pipe each selection through the given external filter program and replace the selection with it’s output.

  • <a-|>: pipe each selection through the given external filter program and ignore its output

  • !: insert command output before selection

  • <a-!>: append command output after selection

  • u: undo last change

  • <a-u>: move backward in history

  • U: redo last change

  • <a-U>: move forward in history

  • &: align selection, align the cursor of selections by inserting spaces before the first character of the selection

  • <a-&>: copy indent, copy the indentation of the main selection (or the count one if a count is given) to all other ones

  • `: to lower case

  • ~: to upper case

  • <a-`>: swap case

  • @: convert tabs to spaces in current selections, uses the buffer tabstop option or the count parameter for tabstop.

  • <a-@>: convert spaces to tabs in current selections, uses the buffer tabstop option or the count parameter for tabstop.

  • <a-)>: rotate selections content, if specified, the count groups selections, so 3<a-"> rotate (1, 2, 3) and (3, 4, 6) independently.

  • <a-(>: rotate selections content backwards

3.9. Goto Commands

Commands beginning with g are used to goto certain position and or buffer. If a count is given prior to hitting g, g will jump to the given line. Using G will extend the selection rather than jump.

3.10. View commands

Commands beginning with v permit to center or scroll the current view. Using V will lock view mode until <esc> is hit

3.11. Marks

Current selections position can be saved in a register and restored later on.

3.12. Jump list

Some commands, like the goto commands, buffer switch or search commands, push the previous selections to the client’s jump list.

3.13. Multi Selection

Kak was designed from the start to handle multiple selections. One way to get a multiselection is via the s key.

For example, to change all occurrences of word 'roger' to word 'marcel' in a paragraph, here is what can be done:

  • select the paragraph with enough x

  • press s and enter roger, then enter

  • now paragraph selection was replaced with multiselection of each roger in the paragraph

  • press c and marcel<esc> to replace rogers with marcels

A multiselection can also be obtained with S, which splits the current selection according to the regex entered. To split a comma separated list, use S then ', *'

The regex syntax supported by Kakoune is the based on the ECMAScript script syntax and is described at :doc regex.

s and S share the search pattern with /, and hence entering an empty pattern uses the last one.

As a convenience, <a-s> allows you to split the current selections on line boundaries.

To clear multiple selections, use space. To keep only the nth selection use n followed by space, in order to remove a selection, use <a-space>.

<a-k> allows you to enter a regex and keep only the selections that contains a match for this regex. Using <a-K> you can keep the selections not containing a match.

C copies the current selection to the next line (or lines if a count is given) <a-C> does the same to previous lines.

$ allows you to enter a shell command and pipe each selection to it. Selections whose shell command returns 0 will be kept, other will be dropped.

3.14. Object Selection

Objects are specific portions of text, like sentences, paragraphs, numbers… Kakoune offers many keys allowing you to select various text objects.

4. Commands

When pressing : in normal mode, Kakoune will open a prompt to enter a command.

Commands are used for non editing tasks, such as opening a buffer, writing the current one, quitting, etc.

4.1. Basic Commands

Some commands take an exclamation mark (!), which can be used to force the execution of the command (i.e. to quit a modified buffer, the command q! has to be used).

Commands starting with horizontal whitespace (e.g. a space) will not be saved in the command history.

  • cd [<directory>]: change the current directory to <directory>, or the home directory if unspecified

  • doc <topic>: display documentation about a topic. The completion list displays the available topics.

  • e[dit][!] <filename> [<line> [<column>]]: open buffer on file, go to given line and column. If file is already opened, just switch to this file. Use edit! to force reloading.

  • w[rite][!] [<filename>]: write buffer to <filename> or use its name if filename is not given. If the file is write-protected, its permissions are temporarily changed to allow saving the buffer and restored afterwards when the write! command is used.

  • w[rite]a[ll]: write all buffers that are associated to a file.

  • q[uit][!] [<exit status>]: exit Kakoune, use quit! to force quitting even if there is some unsaved buffers remaining. If specified, the client exit status will be set to <exit status>.

  • w[a]q[!] [<exit status>]: write the current buffer (or all buffers when waq is used) and quit. If specified, the client exit status will be set to <exit status>.

  • kill[!]: terminate the current session, all the clients as well as the server, use kill! to ignore unsaved buffers

  • b[uffer] <name>: switch to buffer <name>

  • b[uffer]n[ext]: switch to the next buffer

  • b[uffer]p[rev]: switch to the previous buffer

  • d[el]b[uf][!] [<name>]: delete the buffer <name>

  • source <filename>: execute commands in <filename>

  • colorscheme <name>: load named colorscheme.

  • rename-client <name>: set current client name

  • rename-buffer <name>: set current buffer name

  • rename-session <name>: set current session name

  • echo [options] <text>: show <text> in status line, with the following options:

    • -markup: expand the markup strings in <text>

    • -debug: print the given text to the *debug* buffer

  • nop: does nothing, but as with every other commands, arguments may be evaluated. So nop can be used for example to execute a shell command while being sure that it’s output will not be interpreted by kak. :%sh{ echo echo tchou } will echo tchou in Kakoune, whereas :nop %sh{ echo echo tchou } will not, but both will execute the shell command.

  • fail <text>: raise an error, uses <text> as its description

4.2. Multiple commands

Multiple commands can be separated either by new lines or by semicolons, as such a semicolon must be escaped with \; to be considered as a literal semicolon argument.

4.2.1. String syntax and expansions

Values, options and shell context can be interpolated in strings.

5. Configuration & Autoloading

5.1. Kakrc

If not launched with the -n switch, Kakoune will source the ../share/kak/kakrc file relative to the kak binary, which will source additional files:

If the $XDG_CONFIG_HOME/kak/autoload directory exists, load every *.kak files in it, and load recursively any subdirectory.

If it does not exist, falls back to the site wide autoload directory in ../share/kak/autoload/.

After that, if it exists, source the $XDG_CONFIG_HOME/kak/kakrc file which should be used for user configuration.

In order to continue autoloading site-wide files with a local autoload directory, just add a symbolic link to ../share/kak/autoload/ into your local autoload directory.

5.2. Color Schemes

Kakoune ships with some color schemes that are installed to ../share/kak/colors/. If $XDG_CONFIG_HOME/kak/colors/ is present the builtin command colorscheme will offer completion for those color schemes. If a scheme is duplicated in userspace, it will take precedence.

6. Options

Kakoune can store named and typed values that can be used both to customize the core editor behaviour, and to keep data used by extension scripts.

7. Advanced topics

7.1. Faces

Faces describe how characters are displayed on the screen: color, bold, italic…​

See :doc faces.

7.2. Registers

Registers are named lists of text. They are used for various purposes, like storing the last yanked text, or the captured groups associated with the selections.

7.3. Macros

Kakoune can record and replay a sequence of key presses.

7.4. Search selection

Using the * key, you can set the search pattern to the current selection. See :doc keys searching.

7.5. Regex syntax

Kakoune regex syntax is based on the ECMAScript syntax (ECMA-262 standard). It always run on Unicode codepoint sequences, not on bytes.

See :doc regex.

7.6. Exec and Eval

The execute-keys and evaluate-commands are useful for scripting in non interactive contexts.

7.7. Insert mode completion

Kakoune can propose completions while inserting text: filenames, words, lines…

7.8. Escape to normal mode

From insert mode, pressing <a-;> allows you to execute a single normal mode command. This provides a few advantages:

  • The selections are not modified: when leaving insert mode using <esc> the selections can change, for example when insert mode was entered with a the cursor will go back one char. Or if on an end of line the cursor will go back left (if possible).

  • The modes are nested: that means the normal mode can enter prompt (with :), or any other modes (using :on-key or :menu for example), and these modes will get back to the insert mode afterwards.

This feature is tailored for scripting/macros, as it provides a more predictable behaviour than leaving insert mode with <esc>, executing normal mode command and entering back insert mode (with which binding ?)

See :doc modes.

7.9. Highlighters

Manipulation of the displayed text, such as syntax coloration and wrapping is done through highlighters.

7.10. Hooks

Commands can be registered to be executed when certain events arise with hooks.

See :doc hooks.

7.11. Key Mapping

Custom key shortcuts can be registered through mappings.

7.12. Defining Commands

New commands can be created using :define-command.

Some helper commands are available to define composite commands.

7.13. Aliases

With :alias commands can be given additional names. Aliases are scoped, so that an alias can refer to one command for a buffer, and to another for another buffer. The following command defines <alias> as an alias for <command>:

:alias <scope> <alias> <command>

<scope> can be one of global, buffer or window.

:unalias <scope> <alias> [<expected>]

Will remove the given alias in the given scope. If <expected> is specified the alias will only be removed if its current value is <expected>.

7.14. FIFO Buffers

FIFO buffers are very useful for running some commands asynchronously while progressively displaying their result in Kakoune.

7.15. Menus

When a menu is displayed, you can use j, <c-n> or <tab> to select the next entry, and k, <c-p> or <shift-tab> to select the previous one.

Using the / key, you can enter some regex in order to restrict available choices to the matching ones.