YSK there are open-source (gamified) tutorials to learn git
I was trying to learn git and after searching a bit, I finally found some good open-source tutorials. Specifically, I followed those two tutorials, in this order:
PS. Prior to these I had a basic git course, which I think wasn't enough, but probably helped me either way and after this I had checked some git resources, which gave more of a rounded knowledge about git and I think are worth metnioning:
Knowing "how to use" the git command line is an exercise in delusion. You will only know the same small piece the UI tools know and if you get in trouble you're going to stack overflow.
Just my 2¢ but disagree on this one. Where GUIs are usually powerful but inflexible, the CLI is both powerful and flexible. And getting into trouble usually means you have a print on the console that tells you exactly what happened and what concept or command to look up.
Matter of opinion and goals I guess, but if you want to understand git as a tool I recommend learning the CLI.