LINUX: Remotely Force Immediate Reboot

Let’s say you don’t have physically access to a system, and your #sudo reboot or #sudo shutdown -r isn’t working. As long as you have a running session, you can force an immediate reboot remotely via the kernel and using the magic SysRq key.

The magic_SysRq_key provides a way to send a low-level instruction directly to the kernel using /proc.
1. Enable the magic SysRq option by completing the following:
1a. echo 1 > /proc/sys/kernel/sysrq
2. Initiate the reboot. Running this is the equivalent of a forces a hard reset — no shutdown.
2a. echo b > /proc/sysrq-trigger

References:

https://grok.com

https://www.recitalsoftware.com/blogs/17-howto-force-a-immediate-reboot-of-a-remote-linux-machine