As the common code changes, you might want to update your copy to contain the lastest version. To do that, use: cvs -q update Any changes will be merged into the files on your disk, and you should then be up-to-date with your own changes still present. The "-q" option removes a lot of informational messages as CVS enters the various directories in the project; the command still works if you omit it, but it will be harder to see any real error messages.