Fish Shell Guide¶

Fish (Friendly Interactive Shell) is a smart and user-friendly command line shell for Linux, macOS, and other systems. Unlike bash or zsh, Fish is designed to be interactive out of the box with no configuration required.

Key Features¶

Out of the Box - Syntax highlighting - Autosuggestions based on history - Tab completions - Web-based configuration tool

Modern Design - No need to learn shell scripting for basic configuration - Sane defaults - Colorful prompt

Installation¶

macOS

brew install fish

Ubuntu/Debian

sudo apt update
sudo apt install fish

Fedora

sudo dnf install fish

Set as default shell

chsh -s /usr/bin/fish

Configuration¶

Config File Location¶

User config: ~/.config/fish/config.fish

Using the Web UI¶

fish_config

This opens a browser-based configuration tool.

Set Theme¶

fish_config theme choose "Dracula"

Common Commands¶

Aliases (similar to bash)¶

# Create an alias
alias ll 'ls -lah'

# Make it persist (add to config.fish)
alias ll 'ls -lah'
# Then save:
funcsave ll

Abbreviations (recommended over aliases)¶

# Abbreviations expand after pressing space
abbr --add g git
abbr --add gs git status
abbr --add ga git add
abbr --add gc 'git commit -m'
abbr --add gp git push

# Make persistent
funcsave g

Functions¶

# Create a function
function ll
    ls -lah $argv
end

# Save for future sessions
funcsave ll

Useful Functions¶

Git branch in prompt¶

function fish_git_prompt
    if git rev-parse --git-dir >/dev/null 2>&1
        set -l branch (git symbolic-ref --short HEAD 2>/dev/null; or git rev-parse --short HEAD 2>/dev/null)
        if test "$branch"
            echo " ($branch)"
        end
    end
end

# Add to prompt in config.fish
set -g fish_prompt_dirty " ✗"
set -g fish_prompt_clean " ✓"

# cd to directory and list contents
function cl
    cd $argv; and ls
end

Key Differences from Bash¶

Feature	Bash	Fish
Variables	`VAR=value`	`set VAR value`
Export	`export VAR`	`set -x VAR`
Arrays	`arr=(one two)`	`set arr one two`
Conditionals	`if [ $x = "y" ]`	`if test $x = "y"`
Loops	`for i in *.txt`	`for i in *.txt`
Functions	`function name() {}`	`function name\nend`

Environment Variables¶

# Set (temporary)
set PATH $PATH /usr/local/bin

# Set persistently (add to config.fish)
set -gx EDITOR vim

# Unset
set -e VARIABLE_NAME

Tips & Tricks¶

Disable greeting¶

set fish_greeting ""

Use Starship prompt¶

# Install starship
brew install starship

# Add to config.fish
starship init fish | source

Search history¶

# Up/Down arrows search history
# Or use Ctrl+R for reverse search

Auto-cd (no need to type cd)¶

# Fish auto-cds to directories just by typing the path
/home/user/projects
# Automatically cd into it

Wildcards¶

# List all files
ls **/*.txt
# Recursive search

Troubleshooting¶

Fish not starting

# Check for syntax errors in config.fish
fish -n

List all functions bash

Disable functions bracketed paste mode

set fish_bracketed_paste disabled