starship/docs/advanced-config/README.md

Advanced Configuration

While Starship is a versatile shell, sometimes you need to do more than edit starship.toml to get it to do certain things. This page details some of the more advanced configuration techniques used in starship.

::: warning The configurations in this section are subject to change in future releases of Starship. :::

Custom pre-prompt and pre-execution Commands in Bash

Bash does not have a formal preexec/precmd framework like most other shells. Because of this, it is difficult to provide fully customizable hooks in bash. However, Starship does give you limited ability to insert your own functions into the prompt-rendering procedure:

• To run a custom function right before the prompt is drawn, define a new function and then assign its name to starship_precmd_user_func. For example, to draw a rocket before the prompt, you would do

function blastoff(){
    echo "🚀"
}
starship_precmd_user_func="blastoff"

• To run a custom function right before a command runs, you can use the DEBUG trap mechanism. However, you must trap the DEBUG signal before initializing Starship! Starship can preserve the value of the DEBUG trap, but if the trap is overwritten after starship starts up, some functionality will break.

function blastoff(){
    echo "🚀"
}
trap blastoff DEBUG     # Trap DEBUG *before* running starship
eval $(starship init bash)

Change Window Title

Some shell prompts will automatically change the window title for you (e.g. to reflect your working directory). Fish even does it by default. Starship does not do this, but it's fairly straightforward to add this functionality to bash or zsh.

First, define a window title change function (identical in bash and zsh):

function set_win_title(){
    echo -ne "\033]0; YOUR_WINDOW_TITLE_HERE \007"
}

You can use variables to customize this title ($USER, $HOSTNAME, and $PWD are popular choices).

In bash, set this function to be the precmd starship function:

starship_precmd_user_func="set_win_title"

In zsh, add this to the precmd_functions array:

precmd_functions+=(set_win_title)

If you like the result, add these lines to your shell configuration file (~/.bashrc or ~/.zsrhc) to make it permanent.