Restart Ubuntu via keyboard

Solution 1:

SysRq REISUB

Responding to your edited original question: I suggest the 'SysRq REISUB' method. This is a way to reboot linux systems gracefully, that often works to keep the file system healthy (in contrast to hard poweroff).

SysRq is often on the PrintScreen key:

Press Alt + PrintScreen continuously, sometimes the Fn key is involved too (in laptops),

and then slowly (one key after another) the keys R E I S U B to reboot.

When you press the 'letter keys' you need not specify caps lock or shift.

The corresponding sequence to shut down the computer gracefully is:

Press Alt + PrintScreen continuously, sometimes the Fn key is involved too (in laptops),

and then slowly (one key after another) the keys R E I S U O to shut down.

B 'Boot' is replaced by O 'Off'.

You find more details at the following links,

en.wikipedia.org/wiki/Magic_SysRq_key

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