Fish shell cheatsheet

Keys

Shortcut	Description
`Alt ←` / `Alt →`	Move word
`^U`	Delete to beginning
`^W`	Delete to previous `/`
`Alt D`	Delete next word
`Alt ↑`	Last arguments

Help

`Alt H`	Help on word (man)
`Alt W`	Help on word (short descriptions)
`Alt L`	List directory on cursor

Function

Writing functions

function my_function --description "My description"
  ···
end

Conditional

if test -f foo.txt
  ···
else if test -f bar.txt
  ···
else
  ···
end

Combining tests

if test -f foo.txt && test -f bar.txt

if test -f foo.txt -a -f bar.txt

if test \( -f foo.txt \) -a -f \( bar.txt \)

Events

Emitting

emit my_event

Listening

function myhook --on-event my_event
  ···
end

This lets you hook onto events, such as fish_prompt.

Completions

Creating completions

~/.fish/completions/mycommand.fish

complete -c mycommand ...
complete -c mycommand ...
complete -c mycommand ...

Options

complete \
  -c                         # command
  -s                         # short option
  -l                         # long option
  -r, --require-parameter
  -f, --no-files
  -x                         # exclusive (-r -f)
  -n '__fish_use_subcommand' # condition
  --description ".."

Example

  complete -c $cmd \
-n '__fish_use_subcommand' \
-x -a hello \
--description 'lol'

Conditions

Condition	Description
`-n __fish_complete_directories STRING DESCRIPTION`	performs path completion on STRING, allowing only directories, and giving them the description DESCRIPTION.
`-n __fish_complete_path STRING DESCRIPTION`	performs path completion on STRING, giving them the description DESCRIPTION.
`-n __fish_complete_groups`	prints a list of all user groups with the groups members as description.
`-n __fish_complete_pids`	prints a list of all processes IDs with the command name as description.
`-n __fish_complete_suffix SUFFIX`	performs file completion allowing only files ending in SUFFIX. The mimetype database is used to find a suitable description.
`-n __fish_complete_users`	prints a list of all users with their full name as description.
`-n __fish_print_filesystems`	prints a list of all known file systems. Currently, this is a static list, and not dependent on what file systems the host operating system actually understands.
`-n __fish_print_hostnames`	prints a list of all known hostnames. This functions searches the fstab for nfs servers, ssh for known hosts and checks the /etc/hosts file.
`-n __fish_print_interfaces`	prints a list of all known network interfaces.
`-n __fish_print_packages`	prints a list of all installed packages. This function currently handles Debian, rpm and Gentoo packages.
`-n __fish_use_subcommand`
`-n __fish_seen_subcommand_from init`

Example

complete -c ruby -s X -x -a '(__fish_complete_directories (commandline -ct))' --description 'Directory'

Examples

Start each example with complete -c cmdname

-x
  # no filename completion

-s d -x -a "read skip"
  # -d {read|skip}

-s d -x
  # -d <something>

-s f -r
  # -f FILE

-s f -l force
  # -f, --force

-a "(cat /etc/passwd | cut -d : -f 1)"
  # first argument as filename