A while back I presented a solution to a pretty icky problem - how to test for intermittent power issues. Here's a slightly improved version of that script. It keeps the machine on for 2 minutes before shutting down and also keeps an activity log. The delay is also used as the power on interval.
if [[ $USER != "root" ]]; then
echo "This must be run as root"
exit 1
fi
ROOTPW="1234"
DELAY=120
LOGFILE=~/Desktop/poweron.command.log
osascript -e "delay $DELAY"
TIMESTAMP=$(php -r "echo date ('H:i:s"', time() + $DELAY);")
echo $ROOTPW | sudo -S pmset repeat poweron MTWRFSU $TIMESTAMP
echo -n $(date "+%d.%m.%y @ %H:%I:%S") >> $LOGFILE
echo " " $(wc -l $LOGFILE) >> $LOGFILE
osascript -e "tell application "Finder" to shut down"
exit 0