When you accidently change (refactor) the variable name and you have no idea which var is which:

Git diff to the rescue.

There's a reason sed prefers backup when doing in-place replace.

Oh wait, don't tell me you're one of those Windows potatoes coming outta closet. If that's the case boo-fucking-hoo. Visual Studio anyways has an undo.

If not you'll eventually learn to backup and remove in two commands in under couple of seconds - cause you can actually do it yourself.

(Sorry, them windows peeps ranting rustled my jimmies)