From Davor's email to hcoop-sysadmin:

In any case, Etckeeper puts /etc under revision control, git by default, which then behaves like a normal git repository.

That means you can cd /etc, and then execute the most useful commands:

 git log                         (see commit dates & commit msgs)
 git log -p                      (see commits with diff included)
 git add FILE...                 (add FILE to git)
 git diff                        (see any differences since last commit)
 git commit -am "Commit message" (commit your changes after modification)
 git checkout FILE               (override FILE with version from last commit)

With etckeeper installed, this issue of authdaemonrc being overriden would simply be a matter of doing 'git diff', spotting the unwanted changes, and doing 'git checkout courier/authdaemonrc' to restore the file to previous state.

Note that this is not the only mechanism we have for tracking changes to /etc (we use changetrack as well, and I believe mwolson had something that used Mercurial installed), but I'd aim to make etckeeper a new standard.

1. Usage

Each time you make a change, run, for example git commit -a -m "changed blah blah".