linux hardware reboot from software

#/bin/sh

#This script does the same thing as hitting the "reboot" button
#on a machine.

echo 1 > /proc/sys/kernel/sysrq # turns it on
echo s > /proc/sysrq-trigger # sync
echo u > /proc/sysre-trigger # umount ro
echo s > /proc/sysrq-trigger # sync
echo b > /proc/sysrq-trigger # immediate hardware reboot