I'm going to assume you have about as many years of experience as me based on your profile, but if you're going to argue that maintaining this script - for the sole convenience of deleting a branch out from underneath you - is worth it, then there's nothing more I can do to help you.
You're being really dismissive. Handling bad inputs and edge cases, and including help texts, is the sort of requirement that necessitates moving away from one-liners towards a more structured repository.
