shutdown — Halt, power-off or reboot the machine
shutdown [OPTIONS...] [now] [WALL...]
shutdown may be used to halt, power-off or reboot the machine.
The first argument should be the string now which however is ignored by this implementation. Optionally, this may be followed by a wall message to be sent to all logged-in users before going down.
The following options are understood:
--helpPrints a short help text and exits.
-H, --haltHalt the machine.
-P, --poweroffPower-off the machine (the default).
-r, --rebootReboot the machine.
-hEquivalent to
--poweroff, unless
--halt is
specified.
-kDon't halt, power-off, reboot, just write wall message.
--no-wallDon't send wall message before halt, power-off, reboot.