`Tab`	Auto-complete
`Ctrl+F`	Accept autosuggestion
`Alt+Right`	Accept one word
`Alt+Enter`	Accept and execute
`Ctrl+R`	Search history
`Alt+Up`	Previous argument
`Alt+Down`	Next argument
`Alt+L`	List directory
`Alt+P`	Prepend sudo
`Alt+E`	Edit command in editor
`Ctrl+W`	Delete word
`Ctrl+U`	Delete line

Variables

Variable Operations

Setting variables

# Set variable
set name "John"
set -x PATH $PATH /usr/local/bin  # Export

# Universal (persist across sessions)
set -U myvar "value"

# Global (current session)
set -g myvar "value"

# Local (current block)
set -l myvar "value"

# Erase variable
set -e myvar

Arrays

# Create array
set mylist one two three

# Access elements (1-indexed)
echo $mylist[1]      # one
echo $mylist[-1]     # three
echo $mylist[2..3]   # two three

# Count
count $mylist        # 3

# Append
set -a mylist four

# Prepend
set -p mylist zero

Special variables

$status    # Exit status of last command
$argv      # Command line arguments
$fish_pid  # Fish process ID
$USER      # Current user
$HOME      # Home directory
$PWD       # Current directory
$_         # Last argument of previous command

Control Flow

Conditionals

if/else

if test $x -gt 10
    echo "big"
else if test $x -gt 5
    echo "medium"
else
    echo "small"
end

# Short form
test $x -gt 10; and echo "big"; or echo "small"

switch

switch $animal
    case dog
        echo "bark"
    case cat
        echo "meow"
    case '*'
        echo "unknown"
end

Test conditions

test -f file    # Is file
test -d dir     # Is directory
test -e path    # Exists
test -r file    # Readable
test -w file    # Writable
test -x file    # Executable
test -z "$str"  # Empty string
test -n "$str"  # Non-empty string
test $a -eq $b  # Numbers equal
test $a = $b    # Strings equal

Loops

for loop

for i in 1 2 3 4 5
    echo $i
end

# Range
for i in (seq 1 10)
    echo $i
end

# Files
for file in *.txt
    echo $file
end

# Command output
for line in (cat file.txt)
    echo $line
end

while loop

while test $x -lt 10
    echo $x
    set x (math $x + 1)
end

# Read lines
while read -la line
    echo $line
end < file.txt

Loop control

for i in (seq 1 10)
    if test $i -eq 5
        continue  # Skip
    end
    if test $i -eq 8
        break     # Exit loop
    end
    echo $i
end

Functions

Basic function

function greet
    echo "Hello, $argv[1]!"
end

greet World  # Hello, World!

With description

function ll --description "List files in detail"
    ls -la $argv
end

With arguments

function mkcd --description "Make and cd to directory"
    mkdir -p $argv[1]
    cd $argv[1]
end

Event handlers

# Run on directory change
function on_pwd_change --on-variable PWD
    echo "Changed to $PWD"
end

# Run on exit
function on_exit --on-process-exit %self
    echo "Goodbye!"
end

Save function

# Save to file
funcsave function_name

# Edit function
funced function_name

# List functions
functions

# Show function definition
functions function_name

# Erase function
functions -e function_name

Aliases

Create alias

# Alias (wrapper for function)
alias ll="ls -la"
alias gs="git status"

# Or as function
function ll
    ls -la $argv
end

# Save alias
funcsave ll

Abbreviations

# Abbreviations expand when typed
abbr -a gco git checkout
abbr -a gst git status
abbr -a gp git push

# List abbreviations
abbr

# Remove abbreviation
abbr -e gco

String Manipulation

String Commands

String operations

# Length
string length "hello"  # 5

# Substring
string sub -s 1 -l 3 "hello"  # hel

# Replace
string replace "old" "new" "old text"  # new text
string replace -a "o" "0" "foo"  # f00
string replace -r "[0-9]+" "X" "abc123"  # abcX

# Split
string split "," "a,b,c"  # a\nb\nc

# Join
string join "," a b c  # a,b,c

# Trim
string trim "  hello  "  # hello

# Upper/lower
string upper "hello"  # HELLO
string lower "HELLO"  # hello

# Match
string match "*.txt" "file.txt"  # file.txt
string match -r "\d+" "abc123"  # 123

Math

Math Operations

Calculations

math "1 + 2"        # 3
math "10 / 3"       # 3.333...
math "10 % 3"       # 1
math "2 ^ 8"        # 256
math "sqrt(16)"     # 4
math "sin(0)"       # 0
math "round(3.7)"   # 4
math "floor(3.7)"   # 3
math "ceil(3.2)"    # 4

# Assign result
set result (math "1 + 2")

# Scale (decimal places)
math -s 2 "10 / 3"  # 3.33

Configuration

Config Files

config.fish

# ~/.config/fish/config.fish

# Environment variables
set -x PATH $PATH /usr/local/bin
set -x EDITOR vim

# Aliases
alias ll="ls -la"
alias gs="git status"

# Abbreviations
abbr -a gco git checkout

# Greeting
set fish_greeting "Welcome to Fish!"

# Prompt (or use fish_config)
function fish_prompt
    echo -n (prompt_pwd) '> '
end

Fish plugins (Fisher)

# Install Fisher
curl -sL https://git.io/fisher | source && fisher install jorgebucaran/fisher

# Install plugins
fisher install jorgebucaran/nvm.fish
fisher install jethrokuan/z
fisher install PatrickF1/fzf.fish

# List plugins
fisher list

# Remove plugin
fisher remove plugin-name

# Update all
fisher update

Configuration Commands

`fish_config`	Open web configuration
`fish_config theme`	Choose theme
`fish_config prompt`	Choose prompt
`set_color --print-colors`	List colors

History

History Commands

`history`	Show history
`history search pattern`	Search history
`history delete --exact "command"`	Delete specific
`history clear`	Clear all history
`history merge`	Merge histories