cheatsheets/fish-shell.md

title	category	layout	prism_languages	updated	weight
Fish shell	CLI	2017/sheet	fish	2018-01-31	-1

Keys

Shortcut	Description
^A ← / ^E →	Move to line beginning/end
Alt ← / Alt →	Move word
^U	Delete to beginning
^W	Delete to previous /
^D	Delete next character
Alt D	Delete next word
^C	Cancel line
Alt P	Page output
---	---
Alt ↑ / Alt ↓	Previous / next arguments
Alt E / Alt V	Open in external editor
^L	Repaint screen
{: .-shortcuts}

Help

| Alt H | Help on word (man) | | Alt W | Help on word (short descriptions) | | Alt L | List directory on cursor | {: .-shortcuts}

Variables

Defining and erasing

set my_variable "Hello from Fish!"

set --erase my_variable

Incrementing and decrementing

set my_variable (math $my_variable + 1)
set my_variable (math $my_variable - 1)

Slicing

set my_variable $another_variable[1..10]
set my_variable $another_variable[2..]
set my_variable $another_variable[..-2]

Arithmetic

math 1 + 2

Operator	Performs
+	Addition
-	Subtraction
*	Multiplication
/	Division
%	Modulo
^	Exponentiation
{: .-shortcuts}

String manipulation

string match --regex --entire 'Fish' 'Hello from Fish!'

string replace --regex 'Fish' 'fish' 'Hello from Fish!'

Pattern	Matches
x?	Zero or one x chars
x*	Any count x chars
x+	One or more x chars
x{n}	n times x chars
x{n,m}	n to m times x chars
x{n,}	n or more times x chars
x{n,}	n or more times x chars
[xy]	x or y char
[^xy]	not x or y char
{: .-shortcuts}

Class	Description
\w	Word character
\d	Digit character
\W	Not word character
\D	Not digit character
{: .-shortcuts}

Conditionals

if test $my_variable -lt $another_variable
  ···
else if test $my_variable -eq $another_variable
  ···
else
  ···
end

Operator	Meaning
-lt	[L]ess [t]han
-eq	[Eq]ual
-gt	[G]reater [t]han
-le	[L]ess than or [e]qual to
-ge	[G]reater than or [e]qual to
-f	[F]ile exists
-d	[D]irectory exists
-r	File or directory exists and [r]eadable
-w	File or directory exists and [w]ritable
-x	File or directory exists and e[x]ecutable
{: .-shortcuts}

Loops

for i in (seq 1 10)
  ...
end

Command substitution

set my_variable (math $my_variable + 1)

Functions

Defining and erasing

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

functions --erase my_function

Event handling

function my_hook --on-event my_event
  ···
end

Events

Emitting

emit my_event

Abbreviations

Defining and erasing

abbr --add my_abbreviation echo "Hello from Fish!"

abbr --erase my_abbreviation

Completions

Defining and erasing

complete --command mycommand --arguments 'install uninstall'
complete --command mycommand --short-option 'h' --long-option 'help' --description 'Display help'

complete --command mycommand --erase

Option	Description
--arguments	Arguments to command itself or option
--short-option	Short option
--long-option	Long option
--no-files	Don't suggest files
--force-files	Suggest files
--condition	Display hint only when condition is true
--description	Description
{: .-shortcuts}

Useful built-in functions

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