Linux in a Nutshell, 6th Edition

Name

shutdown

Synopsis

shutdown [options] when [message]

System administration command. Terminate all processing. when may be a specific time (in hh:mm format), a number of minutes to wait (in +m format), or now. A broadcast message notifies all users to log off the system. Processes are signaled with SIGTERM to allow them to exit gracefully. /etc/init is called to perform the actual shutdown, which consists of placing the system in runlevel 1. Only privileged users can execute the shutdown command, although init may call shutdown with root privileges when the Ctrl-Alt-Del key combination is pressed from the console keyboard. Broadcast messages, default or defined, are displayed at regular intervals during the grace period; the closer the shutdown time, the more frequent the message.

Options

-a

When called from init, shut down only if one of the users listed in the file /etc/shutdown.allow is currently logged in.

-c

Cancel a shutdown that is in progress.

-f

Reboot fast, by suppressing the normal call to fsck when rebooting.

-F

Force a filesystem check (fsck) on reboot.

-h

Halt or power off the system when shutdown is complete. Which it does depends on system hardware/BIOS.

-H

Halt the system when shutdown is complete.

-k

Print the warning message, but suppress actual shutdown.

-P

Power off the system when shutdown is complete.

-r

Reboot the system when shutdown is complete.