Etckeeper is a collection of tools to let /etc be stored in a git, mercurial, darcs, or bzr repository. It tracks file metadata that revison control systems do not normally support, but that is important for /etc, such as the permissions of /etc/shadow. It's quite modular and configurable, while also being simple to use if you understand the basics of working with revision control. Etckeeper will use git by default although you can change that in /etc/etckeeper/etckeeper.conf, assuming you have other version control tools installed. After installing etckeeper the first time you will need to run "etckeeper init" once to initialize the repository.