shutdown — Halt, power off or reboot the machine
shutdown [OPTIONS...] [TIME] [WALL...]
shutdown may be used to halt, power off, or reboot the machine.
The first argument may be a time string (which is usually
now"). Optionally, this may be followed by a
wall message to be sent to all logged-in users before going
The time string may either be in the format
hh:mm" for hour/minutes specifying the time to
execute the shutdown at, specified in 24h clock format.
Alternatively it may be in the syntax "
referring to the specified number of minutes m from now.
now" is an alias for "
for triggering an immediate shutdown. If no time argument is
+1" is implied.
Note that to specify a wall message you must specify a time argument, too.
If the time argument is used, 5 minutes before the system
goes down the
/run/nologin file is created to
ensure that further logins shall not be allowed.
The following options are understood:
Halt the machine.
Power the machine off (the default).
Reboot the machine.
The same as
--poweroff, but does not override the action to take if
it is "halt". E.g. shutdown --reboot -h means "poweroff", but shutdown
--halt -h means "halt".
Do not halt, power off, or reboot, but just write the wall message.
Do not send wall message before halt, power off, or reboot.
Cancel a pending shutdown. This may be used to cancel the effect of an invocation of
shutdown with a time argument that is not "
Show a pending shutdown action and time if there is any.
On success, 0 is returned, a non-zero failure code otherwise.