Tips for Hard Reboot Linux from Remote SSH

For example you only have remote SSH access to a Linux, but running "reboot" command doesn't work, what can you do?

Run following command for hard reboot:

echo 1 > /proc/sys/kernel/sysrq
echo b > /proc/sysrq-trigger

Or running this for hard shutdown:

echo 1 > /proc/sys/kernel/sysrq
echo o > /proc/sysrq-trigger

NOTE: By running above command no service shutdown script will be execute, not even any disk I/O write back, so only use it for critical issue.