Git is a open-source code version control tool, here are some basic commands to get you going.
BASIC STAGE & COMMIT
Make the current directory a git repository: $ git init
Add files to the repository ready for the next commit: $ git add .
Add/delete files to the repository ready for the next commit: git add . -A
Commit the files with a comment: $ git commit -m "initial commit"
Stage & commit at the same time: $ git commit -am 'update to index.php'