etckeeper allows the contents of /etc be easily stored in Version Control System (VCS) repository. It hooks into apt to automatically commit changes to /etc when packages are installed or upgraded. Placing /etc under version control is considered an industry best practice, and the goal of etckeeper is to make this process as painless as possible.

Install etckeeper by entering the following in a terminal:

sudo apt-get install etckeeper

The main configuration file, /etc/etckeeper/etckeeper.conf, is fairly simple. The main option is which VCS to use. By default etckeeper is configured to use bzr for version control. The repository is automatically initialized (and committed for the first time) during package installation. It is possible to undo this by entering the following command:

sudo etckeeper uninit

By default, etckeeper will commit uncommitted changes made to /etc daily. This can be disabled using the AVOID_DAILY_AUTOCOMMITS configuration option. It will also automatically commit changes before and after package installation. For a more precise tracking of changes, it is recommended to commit your changes manually, together with a commit message, using:

sudo etckeeper commit "..Reason for configuration change.."

Using the VCS commands you can view log information about files in /etc:

sudo bzr log /etc/passwd

To demonstrate the integration with the package management system, install postfix:

sudo apt-get install postfix

When the installation is finished, all the postfix configuration files should be committed to the repository:

Committing to: /etc/
added aliases.db
modified group
modified group-
modified gshadow
modified gshadow-
modified passwd
modified passwd-
added postfix
added resolvconf
added rsyslog.d
modified shadow
modified shadow-
added init.d/postfix
added network/if-down.d/postfix
added network/if-up.d/postfix
added postfix/dynamicmaps.cf
added postfix/main.cf
added postfix/master.cf
added postfix/post-install
added postfix/postfix-files
added postfix/postfix-script
added postfix/sasl
added ppp/ip-down.d
added ppp/ip-down.d/postfix
added ppp/ip-up.d/postfix
added rc0.d/K20postfix
added rc1.d/K20postfix
added rc2.d/S20postfix
added rc3.d/S20postfix
added rc4.d/S20postfix
added rc5.d/S20postfix
added rc6.d/K20postfix
added resolvconf/update-libc.d
added resolvconf/update-libc.d/postfix
added rsyslog.d/postfix.conf
added ufw/applications.d/postfix
Committed revision 2.

For an example of how etckeeper tracks manual changes, add new a host to /etc/hosts. Using bzr you can see which files have been modified:

sudo bzr status /etc/
modified:
  hosts

Now commit the changes:

sudo etckeeper commit "new host"

For more information on bzr see the section called “Bazaar”.