I haven’t looked closely yet, but this looks interesting: Write yourself a Git.
It’s not a joke, and it’s really not complicated: if you read this article top to bottom and write the code (or just clone the repository — but you should write the code yourself, really), you’ll end up with a program, called
wyag, that will implement all the fundamental features of git:
log… in a way that is perfectly compatible with
gititself. The last commit of this article was actually created with
git. And all that in exactly 503 lines of very simple Python code.
Edit: here’s a related tutorial:
Build yourself a Distributed Version Control System (just like Git)