Howtoforge posted a tutorial about how you can store the contents of your /etc directory in a version control system (VCS) with the help of etckeeper on Debian Squeeze.

etckeeper hooks into Debian's package manager apt so that whenever you install/remove a package with apt, etckeeper will commit all changes to the /etc directory to your VCS; it also tracks file metadata such as permissions which is important for files such as /etc/shadow. Using etckeeper, you can go back to a previous version of /etc if an update has overwritten valuable configuration files. Not only will etckeeper track apt's changes to /etc, it will also do a daily auto-commit so that your manual changes go to VCS as well; in addition to that, you can do commits at any time manually.

  Using Version Control For Your /etc Directory With etckeeper And Bazaar On Debian Squeeze