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.