Secure Bash Prompt

I like the functionality of custom shell prompts like Starship but also think they're a security liability to have installed on the workstation of someone that may have access to sensitive environments, like myself. I don't have the time or motivation to audit 1000s of lines of code.

This project is an attempt to write some of the functionality of the fancy prompts in a secure and minimal way, a couple of hundred lines of pure Bash at the maximum. It should be easy to audit.

Usage

TODO: update with advice on locals and unset -f

• Copy the contents of prompt_command.sh to your $HOME/.bashrc file.
• Customise the PS1 variable as you'd like the prompt to look.
• Extra functionality is available in functions.sh. To use this file, put it somewhere safe from other non-root users in your home directory, remove POSIX permissions other than your user, then source the absolute path to the file.
• Using functions.sh is optional and you can use as much or as little as you like. You may wish to start with a blank file and slowly add things.
• It's designed to play nicely with old school PS1 generation tools like https://bash-prompt-generator.org/.
• source $HOME/.bashrc.

More info

It's for GNU/Linux and GNUified MacOS. I don't envisage this being POSIX compliant or supporting anything other than GNU userland/Bash. You're welcome to fork though.

It's intended to be highly modular such that people can pick/choose the functionality they want and don't have to audit code for functionality that is not required.

I value responsiveness of the prompt so features that take too much time to execute will not be accepted. Given a press of return, a new prompt should appear almost immediately.

I originally started writing it last year but got distracted/lost motivation because it was good enough for me then. The original code isn't very readable and has the odd bug. I'm writing a neater version here.

I am not going to try and replicate the entire functionality of the less than ideal code all at once but rather do it in small chunks, when I can.

I'm making it open source in the hope other people may contribute new functionality and help fix bugs.