Anatomy of the Prompt

What the prompt actually is

The prompt is a string the shell prints before each command. Bash stores it in $PS1, zsh in $PROMPT (or $PS1; both work). It is just text with escape codes — your shell evaluates these every time it gets ready for input. That means a great prompt is a few characters of expansion, not a plugin.

The escape codes you'll see most

• %n / \u — username
• %m / \h — short host
• %~ / \w — current dir, with ~ for home
• %? / $? — exit code of the last command
• %F{red} / \[\033[31m\] — color start (zsh / bash)
• %f / \[\033[0m\] — color reset

If you read someone's .zshrc and see PROMPT='%F{cyan}%n%f@%m %~ %F{red}%(?..%?)%f%# ', that decodes to: cyan username, regular host, working directory, red exit code only when non-zero, then the prompt character.

Multi-line prompts and right-side prompts

You can split the prompt onto two lines so commands always start at the left margin. Set PROMPT to one line ending in $'\n' and a short final glyph. Zsh also exposes RPROMPT, which prints on the right of the same line — perfect for git branch info that doesn't push your typing area around.

Themed prompts you don't write yourself

You don't have to hand-craft escape codes. Powerlevel10k (zsh) and Starship (any shell) generate fast, async, info-rich prompts: git status, Python venv, Node version, Kubernetes context, AWS profile, last-command duration. Write your own only if you enjoy it; otherwise pick Starship and move on.