I use org-mode a lot. Because my files change a lot and I want to preserve the history and to be able to synchronize them with my freerunner, I use git to track my org files.

However, I did this just in theory, in reality I was just too lazy. So this is how you get a commit whenever you save your changes:

First, install incron. This is a program like cron, but it responds to filesystem events. apt-get install incron should be enough

Second, create a script like the following:

#! /bin/sh
cd /home/arne/org # <- the path to your files
git commit -a -m auto

Third, create a git repository for the files you want to track:

cd /home/arne/org
git init
git add ${FilesYouWantToTrack}

And last, create a incrontab entry:

sudo echo YourUsername >> /etc/incron.allow
incrontab -e
write s.th. like this into the editor: /home/arne/org/ IN_MODIFY /home/arne/bin/commit-org

This rule says that everytime a file in /home/arne/org is modified (IN_MODIFY), the script /home/arne/bin/commit-org is executed. Adjust those paths to your needs.

That's it. If you want to track additional files in that directory, a simple "git add" is enough. Everytime you save a tracked file, a new commit will be created in the background.