Squirrel-cfg is a system that collects (system) configuration files and saves a copy in a version management system, currently this is CVS. Normally squirrel is periodically started by the cron system.
Currently I started developing on this application again. I'm doing a full rewrite. It will be written in Python and is placed on top of Subversion. Shortly initial versions will be available in the repository.
why this program ? Many reasons. It started when I created a Linux configuration manually and then started linuxconf. Which, of course does a great job, but did change something that caused my system to behave differently. Since such things had happened to me before, not only on Linux btw, I started looking for configuration backup utilities
Note that eventhough you do your systemmaintenance using vi, you are still confronted with the situation where tools change configuration files. For example, package managers are often instructed to add or remove user entries from the Unix password file. Depending on the package manager, the administrator may not be notified of this event.
So the benefits of a system that periodically collects changed (system) configuration files are clear. Besides having a better historical picture of your system, one gets a much better understanding of the files that belong to a package. The hsitorical view of system even gets better when the list of installed packages is periodically added to the list of saved files.
Other fields of use of the program could be auditing and reverse engineering.
Personally I use the tools for tracking changes in development which are not yet commit to the development repository. This way I can always recover my work even if files get accidentally removed.