This allows sending of SysRq keys[1]. This then for example allows
sending the well known 'reisub' commands to safely reboot a otherwise
frozen Linux box. Or obviously any of the other magic keys.
The advantage compared to sending it to /proc/sysrq-trigger is that one
does not need a shell and depending on how broken the system is, one
might not even be able to get a new shell. The SysRq keys still work.
The cost is adding a new/"non-standard" keyword, IMO it is worth it.
Example:
DEFAULTDELAY 200
DELAY 1000
SYSRQ r
SYSRQ e
SYSRQ i
SYSRQ s
SYSRQ u
SYSRQ b
If one really wants to test it, I suggest h(elp) or w(ait).
[1] https://en.wikipedia.org/wiki/Magic_SysRq_key
Co-authored-by: Aleksandr Kutuzov <alleteam@gmail.com>