This page gives brief, visual reference for the most common commands in git. Once you know a bit about how git works, this site may solidify your understanding.
I have been using git for a while, and I took the time to learn about it in great detail. Equipped with an understanding of its internals and a comfortable familiarity with tools like git rebase — and a personal, intrinsic desire to strive for minimal and lightweight solutions — I have organically developed a workflow which is, admittedly, somewhat unorthodox.
Easily create beautiful UML Diagrams from simple textual description. There are also numerous kind of available diagrams. It's also possible to export images in PNG, LaTeX, EPS, SVG.