what’s a simple command or script that felt like a magic trick once you learned it?

We all have that moment where you discover a command or a one-liner that saves you from a ton of manual work and you wonder how you ever lived without it.

For me, it was learning about rsync -avP for large transfers. Going from a blind cp that could silently fail for hours to seeing the progress and file list in real-time was a game-changer.

A close second is cd - to jump back to the previous directory.