Editing configuration files on servers can be risky and so most cautious admins will backup any files they change. However, creating backups and trying to maintain multiple versions of configuration files can be tedious. You could use CVS but that’s overkill for a single file. Enter RCS.
You can download the source from the main GNU ftp site (ftp.gnu.org) and install it the usual way (.configure; make install).
To check in a file, use:
If this file is new or updated you will be prompted to enter a comment. Checking in the file will also remove it so you will need to check it out after if it needs to be available.
To check out a file, use:
Checkout out the file this way opens the file in “shared” mode, so the file only has read permissions set.
If you want to check out the file and make changes you must use:
co -l filename