Prompt Customization¶

The prompt is what you see before typing commands. Customizing it can improve your workflow by showing useful information at a glance.

Prompt Variables¶

Variable	Purpose
`PS1`	Primary prompt (what you see)
`PS2`	Continuation prompt (after `\`)
`PS3`	Select menu prompt
`PS4`	Debug trace prefix

Basic PS1¶

Default prompts look like:

user@hostname:~$

Set a custom prompt:

PS1='$ '                           # Minimal
PS1='\u@\h:\w\$ '                  # user@host:path$

Escape Sequences¶

Special sequences expand to information:

Sequence	Meaning
`\u`	Username
`\h`	Hostname (short)
`\H`	Hostname (full)
`\w`	Working directory (full)
`\W`	Working directory (basename)
`\d`	Date (Tue May 26)
`\t`	Time (24h HH:MM:SS)
`\T`	Time (12h HH:MM:SS)
`\@`	Time (12h am/pm)
`\A`	Time (24h HH:MM)
`\n`	Newline
`\r`	Carriage return
`\\`	Literal backslash
`\$`	`$` for user, `#` for root
`\[`	Start non-printing sequence
`\]`	End non-printing sequence
`\!`	History number
`\#`	Command number
`\j`	Number of background jobs

Color Codes¶

ANSI Colors¶

Wrap colors in \[ and \] so bash knows they don't take space:

# Format: \[\e[CODEm\]
# Reset: \[\e[0m\]

RED='\[\e[31m\]'
GREEN='\[\e[32m\]'
YELLOW='\[\e[33m\]'
BLUE='\[\e[34m\]'
MAGENTA='\[\e[35m\]'
CYAN='\[\e[36m\]'
WHITE='\[\e[37m\]'
RESET='\[\e[0m\]'

PS1="${GREEN}\u${RESET}@${BLUE}\h${RESET}:${YELLOW}\w${RESET}\$ "

Extended Colors¶

256 colors and bold/dim:

# Bold
BOLD='\[\e[1m\]'

# 256 colors: \[\e[38;5;COLORm\]
ORANGE='\[\e[38;5;208m\]'
PURPLE='\[\e[38;5;141m\]'

PS1="${BOLD}${ORANGE}\u${RESET}:${PURPLE}\w${RESET}\$ "

Practical Prompt Examples¶

Minimal¶

PS1='\$ '

Classic¶

PS1='\u@\h:\w\$ '

user@host:~/projects$

Colorful¶

PS1='\[\e[32m\]\u\[\e[0m\]@\[\e[34m\]\h\[\e[0m\]:\[\e[33m\]\w\[\e[0m\]\$ '

Two-Line¶

PS1='\[\e[34m\]\w\[\e[0m\]\n\[\e[32m\]\u\[\e[0m\]$ '

~/projects/myapp
user$

With Time¶

PS1='[\A] \u:\w\$ '

[14:30] user:~/projects$

With Exit Code¶

PS1='$(if [ $? -eq 0 ]; then echo "\[\e[32m\]o\[\e[0m\]"; else echo "\[\e[31m\]x\[\e[0m\]"; fi) \w\$ '

Shows green o for success, red x for failure.

Dynamic Prompts¶

Using PROMPT_COMMAND¶

PROMPT_COMMAND runs before each prompt:

PROMPT_COMMAND='echo -n "$(date +%H:%M) "'
PS1='\w\$ '

Or use it to update PS1:

set_prompt() {
    local exit_code=$?
    local red='\[\e[31m\]'
    local green='\[\e[32m\]'
    local reset='\[\e[0m\]'

    if [[ $exit_code -eq 0 ]]; then
        PS1="${green}>${reset} "
    else
        PS1="${red}>${reset} "
    fi
}
PROMPT_COMMAND=set_prompt

Git Branch in Prompt¶

Show current git branch:

parse_git_branch() {
    git branch 2>/dev/null | grep '^*' | sed 's/* //'
}

PS1='\w $(parse_git_branch)\$ '

With color and formatting:

parse_git_branch() {
    local branch
    branch=$(git branch 2>/dev/null | grep '^*' | sed 's/* //')
    [[ -n "$branch" ]] && echo "($branch) "
}

PS1='\[\e[34m\]\w\[\e[0m\] \[\e[33m\]$(parse_git_branch)\[\e[0m\]\$ '

~/projects/myapp (main) $

Git Status Indicator¶

git_prompt() {
    local branch
    branch=$(git branch 2>/dev/null | grep '^*' | sed 's/* //')
    [[ -z "$branch" ]] && return

    local status=""
    git diff --quiet 2>/dev/null || status="*"
    git diff --cached --quiet 2>/dev/null || status="${status}+"

    echo "($branch$status) "
}

PS1='\w $(git_prompt)\$ '

Shows * for unstaged changes, + for staged changes.

Starship Prompt¶

Starship is a modern, cross-shell prompt that's highly recommended:

Install¶

# macOS
brew install starship

# Linux
curl -sS https://starship.rs/install.sh | sh

Enable¶

Add to end of ~/.bashrc:

eval "$(starship init bash)"

Configure¶

Create ~/.config/starship.toml:

# Minimal config
format = """
$directory$git_branch$git_status$character"""

[character]
success_symbol = "[>](bold green)"
error_symbol = "[>](bold red)"

[directory]
truncation_length = 3
truncate_to_repo = true

[git_branch]
format = "[$branch]($style) "
style = "bold yellow"

[git_status]
format = '([$all_status$ahead_behind]($style) )'

Starship Advantages¶

Cross-shell (bash, zsh, fish, PowerShell)
Fast (written in Rust)
Extensive customization
Built-in git, language version, cloud context support
Active development

Common Prompt Configurations¶

Developer Prompt¶

# Shows: user, directory, git, virtualenv
dev_prompt() {
    local git_branch
    git_branch=$(git branch 2>/dev/null | grep '^*' | sed 's/* //')

    local venv=""
    [[ -n "$VIRTUAL_ENV" ]] && venv="($(basename $VIRTUAL_ENV)) "

    PS1="${venv}\[\e[32m\]\u\[\e[0m\]:\[\e[34m\]\w\[\e[0m\]"
    [[ -n "$git_branch" ]] && PS1+=" \[\e[33m\]($git_branch)\[\e[0m\]"
    PS1+="\$ "
}
PROMPT_COMMAND=dev_prompt

Server Prompt¶

Highlight root and show hostname:

if [[ $EUID -eq 0 ]]; then
    PS1='\[\e[31m\]\u@\h\[\e[0m\]:\w# '
else
    PS1='\[\e[32m\]\u\[\e[0m\]@\h:\w\$ '
fi

Minimal Fast Prompt¶

Keep it simple for speed:

PS1='\w \$ '

PS2, PS3, PS4¶

PS2 - Continuation¶

When command continues to next line:

PS2='... '

echo "this is \
... a continued line"

Used by select command:

PS3="Choose an option: "
select opt in "One" "Two" "Quit"; do
    echo "You chose: $opt"
    [[ $opt == "Quit" ]] && break
done

PS4 - Debug Trace¶

Prefix for set -x output:

PS4='+ ${BASH_SOURCE}:${LINENO}: '
set -x
echo "debug"
set +x

+ /home/user/script.sh:10: echo debug
debug

Troubleshooting¶

Prompt Wraps Incorrectly¶

Non-printing characters must be wrapped:

# Wrong - causes wrapping issues
PS1='\e[32m\u\e[0m$ '

# Correct
PS1='\[\e[32m\]\u\[\e[0m\]$ '

Prompt is Slow¶

Git operations can slow prompts. Cache or simplify:

# Fast git branch
__git_ps1() {
    git symbolic-ref --short HEAD 2>/dev/null
}

Or use Starship which is optimized for speed.

Colors Don't Work¶

Check terminal supports colors:

echo $TERM       # Should be xterm-256color or similar
tput colors      # Should show 256

Try It¶

Basic customization:
```
PS1='\u:\w\$ '
```

Add colors:

PS1='\[\e[32m\]\u\[\e[0m\]:\[\e[34m\]\w\[\e[0m\]\$ '

Add git branch:

parse_git_branch() {
    git branch 2>/dev/null | grep '^*' | sed 's/* / /'
}
PS1='\w$(parse_git_branch)\$ '

Try Starship:

brew install starship
eval "$(starship init bash)"

Summary¶

Variable	Purpose
`PS1`	Main prompt
`PS2`	Continuation prompt
`PS3`	Select menu prompt
`PS4`	Debug trace prefix
`PROMPT_COMMAND`	Run before each prompt

Key escape sequences:

Sequence	Meaning
`\u`	Username
`\h`	Hostname
`\w`	Full path
`\W`	Current directory
`\$`	$ or #
`\[...\]`	Non-printing (colors)

For most users, Starship is recommended for a modern, fast, customizable prompt.