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 ~/.zshrc) to make it permanent.

For example, if you want to display your current directory in your terminal tab title, add the following snippet to your ~/.bashrc or ~/.zshrc:

function set_win_title(){
    echo -ne "\033]0; $(basename "$PWD") \007"
}
starship_precmd_user_func="set_win_title"

Style Strings

Style strings are a list of words, separated by whitespace. The words are not case sensitive (i.e. bold and BoLd are considered the same string). Each word can be one of the following:

• bold
• italic
• underline
• dimmed
• inverted
• bg:<color>
• fg:<color>
• <color>
• none

where <color> is a color specifier (discussed below). fg:<color> and <color> currently do the same thing, though this may change in the future. inverted swaps the background and foreground colors. The order of words in the string does not matter.

The none token overrides all other tokens in a string if it is not part of a bg: specifier, so that e.g. fg:red none fg:blue will still create a string with no styling. bg:none sets the background to the default color so fg:red bg:none is equivalent to red or fg:red and bg:green fg:red bg:none is also equivalent to fg:red or red. It may become an error to use none in conjunction with other tokens in the future.

A color specifier can be one of the following:

• One of the standard terminal colors: black, red, green, blue, yellow, purple, cyan, white. You can optionally prefix these with bright- to get the bright version (e.g. bright-white).
• A # followed by a six-digit hexadecimal number. This specifies an RGB color hex code.
• A number between 0-255. This specifies an 8-bit ANSI Color Code.

If multiple colors are specified for foreground/background, the last one in the string will take priority.