HowtoMatrix

Sometimes the machine you’re working on has a little oops. Maybe the
reboot command has hung and the system will not shutdown or a kernel
panic has occurred and although you still have shell access, there is
little more you can do with the machine. The solution is simple: you
need to hard reboot the machine. But you’re in Phoenix and the machine
is in L.A. Like any good system administrator, you have the machine
hooked up to an IP-KVM (or serial over IP, if the machine is headless),
but the magic SysRq keys won’t send properly. So what’s a sysadmin to
do?

The solution is amazing simple and stems from the SysRq key command
to reboot the machine. As it happens, you can send SysRq commands to a
machine without using a keyboard via the proc interface.

Read more at The Open Source Journal