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using sysrq to reboot when systemd is broken

This script comes from Bob Proulx:

#!/bin/sh
echo 1 >/proc/sys/kernel/sysrq
echo s >/proc/sysrq-trigger
echo b >/proc/sysrq-trigger

It may also be worth trying to manually kill important processes first, so they have a chance to write out any state to disk before the system halts and immediately reboots.