while true
do
date >> /var/log/perfmon.log
vmstat 3 10 >> /var/log/perfmon.log
sleep 300
done

but instead of giving a sleep of 5 minutes why don't you cron the whole thing. Schedule the commands so that they run after every 5 min.

Amit

Originally that's what I was going to do, however the particular box I am trying to get this running on has had cpu spike issues that cause crons to fail during the spikes. Hoping that an active process may have more luck staying active than a new process starting. Am also going to collect data for a specific interval, write to file then tar the files by date/time. Wasn't sure how to do that by cron. Anyway, got it working the way I wanted it until the real scripting guy gets back from vacation thanks!