How Can I Improve My Bash Script for Installing Software?

I took a quick look at your script, and here are a few pointers:
1. Make sure to check if the script is run as root to avoid permission issues.
2. When detecting the package manager, you might want to streamline how you check with `command -v`. It's good practice to handle errors with `printf` to stderr rather than using `echo`.
3. You may want to structure your conditional branches more clearly using `case` for cleaner code. Keep improving your coding style!

Consider installing and running this tool called ShellCheck. It provides really helpful advice on improving shell scripts. It's available on most Linux distros and could save you some time with best practices!

If this script is just for your personal use, you might want to customize it specifically for your own setup, rather than making it generic for different users. Here’s a link to my own setup script that might give you some ideas: [https://github.com/adityaathalye/bash-toolkit/blob/master/machine-setup.sh](https://github.com/adityaathalye/bash-toolkit/blob/master/machine-setup.sh)

You might want to check out the 'select' case method for creating menus in your script. It's a more organized way to handle adding new items since it automatically takes care of the numbering for you. Also, just a heads up—your NixOS configuration has your admin password in it, which could be a security concern!