If your Linux system is frozen completely and there is absolutely no response and you are planning to unplug the power cable for hard reboot, there is a way to graciously reboot the system without unplugging the cable.

First of all ensure that your system is actually frozen:

Try Ctrl+Alt+Backspace combination if you are using graphical mode. If it doesn’t work, then try “Ctrl+Alt+F1“, “Ctrl+Alt+F2” etc to see if you can get to a shell in text mode.

If the Linux system doesn’t respond to any of the above attempts, you can do the following to graciously reboot the system.

  • Press Alt+SysReq
  • Press the following sequence of keys with some time delay in between
    • R S E I U B

Each key has a special meaning after pressing Alt+SysReq.

R Take keyboard out of raw mode
S Synchronize the disk
E Terminates all processes
I Kill all processes
U Remount all file systems in read-only mode
B Reboot the system