shutdown
This command is similar to the restart command, but it simply shuts the computer down and does not reboot.
If the optional delay-seconds parameter is provided, the shutdown will happen
automatically after the specified delay.
If a user is logged in, a UI will be displayed that shows the delay counting down. In this case, the UI will have a Shutdown Now button instead of a Cancel button. If the delay parameter is not specified, the user is prompted to press a button to shut down the computer
| Version | Platforms | 
|---|---|
| 8.0.584.0 | AIX, HP-UX, Mac, Red Hat, SUSE, Solaris, Windows | 
| 8.1.535.0 | Debian, Ubuntu | 
Syntax
shutdown [delay-seconds]
Where delay-seconds is an optional parameter to provide a delay before
shutting down.
Examples
This command will shut down the computer in three minutes.
shutdown 180Notes
The delayed shutdown is a forced shutdown. It will not prompt the user to save changes to documents, etc. The machine will shut down without further prompting.