The Revision Control System (RCS) tool is a lightweight utility for versioning individual files. All revisions, access logs, permissions, and so forth are being kept in a single text file, which is really easy to create on the fly. I have used RCS to version server config files. That way, you can easily back out of any changes quickly in case you break the configuration and the service goes down completely. It also makes it easy to review and revert to previous configurations even if it is long after you have already forgotten the actual changes you made to the file.
You can visit the official RCS homepage as a starting point for learning more about this tool. There, you can also find download links to the current source code, binaries for various platforms, and the original paper that inspired the creation of RCS:
http://www.cs.purdue.edu/homes/trinkle/RCS/
RCS comes with a cast of supporting utilities that turn its basic functionality into a functioning...