Perl for System Administration

Appendix A. The Five-Minute RCS Tutorial

This quick tutorial will teach you everything you need to know about how to use Revision Control System (RCS) for system administration. RCS has considerably more functionality than we’ll discuss here, so be sure to take a look at the manual pages and the reference at the end of this appendix if you plan to use it heavily.

RCS functions like a car rental agency. Only one person at a time can actually rent a particular car and drive it off the lot. A new car can only be rented after the agency has added it to their pool. Customers can browse the list of cars (and their features) at any time, but if two people want to rent the same car, the second must wait for the car to be returned to the lot before renting it. Finally, car rental agencies inspect cars very carefully after they have been returned and record any changes to the car during the rental. All of these properties hold true for RCS as well.

In RCS, a file is like a car. If you wish to keep track of a file using RCS (i.e., add it to the rental lot) you “check it in” for the first time:

$ ci -u 
         filename

ci stands for “check in,” and the -u tells RCS to leave the file in place during the check-in. When a file is checked in (i.e., made available for rental), RCS does one of two things to remind the user that the file is under RCS’s control:

1. Deletes the original file, leaving only the RCS archive file behind. This archive file is usually called filename,v and is either kept in the same directory ...