Oh Shit Git
There are lots of people who can help you understand Git. Some of them are quite exhaustive, like Dan Gitcodeschooldude (who I covered here). His free video tutorials are great. But they’re also unequivocally not a cheat sheet. They’re essentially in-depth tutorials that will give you incredibly deeper understanding but require sustained focus.
As its GitHub documentation notes, the single-file PHP script searchreplacedb2 is “not terribly pretty, but it’s portable and it solves an important problem that comes up whenever WordPress sites get renamed.”