Linux "shutdown" Command Line Options and Examples
Halt, power-off or reboot the machine
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 down.
shutdown [OPTIONS...] [TIME] [WALL...]
Command Line Options:
Print a short help text and exit.
shutdown --help ...
Halt the machine.
shutdown -H ...
Power-off the machine (the default).
shutdown -P ...
Reboot the machine.
shutdown -r ...
Equivalent to --poweroff, unless --halt is specified.
shutdown -h ...
Do not halt, power-off, reboot, just write wall message.
shutdown -k ...
Do not send wall message before halt, power-off, reboot.
shutdown --no-wall ...
Cancel a pending shutdown. This may be used cancel the effect of an invocation of shutdown with a timeargument that is not "+0" or "now".EXIT STATUSOn success, 0 is returned, a non-zero failure code otherwise.
shutdown -c ...