[CentOS] Limit RAM used by a perl script

Mon Jul 20 15:28:00 UTC 2009
Sean Carolan <scarolan at gmail.com>

I have a perl script which runs from a cron job.  How would you limit
the amount of RAM that this script is allowed to consume?  Is there a
ulimit setting that will accomplish this?  If so does ulimit have to
be run each time the script is run, or is there a way to set it
permanently?