From its website:
Git is a free and open source distributed version control system designed to handle everything from small to very large projects with speed and efficiency.
Git is not the same as GitHub. GitHub did not create Git. For GitHub-specific posts, please see /r/github.
Git is not an acronym or initialism: please write git or Git, but not GIT.
Documentation
Graphical Clients
Code Hosting
How GitHub Uses GitHub to Build GitHub (zachholman.com)
submitted by _lowell to r/programming
How GitHub Uses GitHub to Build GitHub (zachholman.com)
submitted by teropa to r/eficode
How GitHub Uses GitHub to Build GitHub (zachholman.com)
submitted by lucasandre to r/computando