Installing & using etckeeper in Ubuntu 9.04

Etckeeper is a collection of tools to store /etc in a version control system. It allows you to read the changes that have been made to the files in /etc, document these changes and recover a previous version of a modified file in case we made some changes that we don’t want to keep.

Its installation is trivial:

apt-get install etckeeper

By default, Bazaar Distributed Version Control System is used, but you can use Git, Mercurial or Darcs instead. You just have to edit its configuration file (/etc/etckeeper/etckeeper.conf) and uncomment the line with your favorite DVCS (and comment the line VCS=”bzr” if you don’t want to use Bazaar).

To initialize etckeeper use:

etckeeper init

To make your first commit to etckeeper use:

etckeeper commit "Initial commit"

Any time you make a change to any file in /etc and you want to document it, use the previous command with the corresponding explanation.

Changes to /etc before installing new software using dpkg or apt are kept automatically by default. You can change this by editing its configuration file and uncommenting “AVOID_COMMIT_BEFORE_INSTALL=1″. Besides, etckeeper commits changes automatically every day, so if you want to avoid it, uncomment “AVOID_DAILY_AUTOCOMMITS=1″ in its configuration file.

Here are some useful commands to take advantage of etckeeper if you use Bazaar DVCS:

• To show etckeeper’s history:

  bzr log --line /etc

• To show differences between the last version and the current state of /etc:

  bzr diff /etc

• To show changes in version X:

  bzr diff -cX /etc

• To recover version X of a FILE:

  bzr revert -rX /etc/FILE