etckeeper is a tool to keep configuration files in a version control system (git, bazaar or mercurial). The Debian package management tools (apt-get, aptitude) integrate with etckeeper so that configuration is version controlled during updates.
Installation
Installation is done using apt-get or aptitude. The default VCS used by etckeeper is git.
aptitude install etckeeper etckeeper init
(more recent versions of etckeeper are automatically initialized by aptitude/apt-get).
Notes for Debian Etch
etckeeper is available for Etch via the backports.org service. To use it you have to add the following line to your /etc/apt/sources.list
deb http://www.backports.org/debian etch-backports main
There are some instructions for using backports at http://backports.org/dokuwiki/doku.php?id=instructions
Usage
Perform commit of changes to /etc
etckeeper commit [message]
Watch the commit logs
cd /etc git log
The rest is just git operations as documented in the fine git documentation.