It's not hard to create and run a shell script in Linux distros like Ubuntu, but there are a few non-obvious pitfalls you need to avoid. Here's a quick example of how to execute a script in Linux.

To get a list of the bash builtins, just type “help” when you’re on the bash command line. For more about built-ins, refer to “ How to tell if you’re using a bash builtin ”.

If you use sudo you can automatically re-start scripts that need to be run as root by adding a check at the beginning of the script and executing sudo if the script is not running as root: ...