Reverting cvs codebase with -D

Open Source Development With CVS: "floss$ cvs -q update -D '1999-04-19'
U hello.c
U a-subdir/subsubdir/fish.c
U b-subdir/random.c
floss$

With the -D option, update retrieves the highest revision of each file as of the given date, and it will revert the files in the working copy to prior revisions if necessary. "