For each file that you want to be notified about, you enter the following command:
$ cvs watch add filename
If you omit the filename(s), a watch will be added for all files in the directory tree.
There are three actions you can be notified about: commit, edit, and unedit.
For instance, to be notified only about commits, you enter the following command:
$ cvs watch add -a commit filename
You can see who is watching a file with cvs watchers:
$ cvs watchers hello.py hello.py dyork edit unedit commit fred commit $
Without a filename, it shows all files that are being watched.