Terminates all processing.
when may be a specific time (in
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. Only privileged users can execute the shutdown command. Broadcast messages, default or defined, are displayed at regular intervals during the grace period; the closer the shutdown time, the more frequent the message.
Halt the system when shutdown is complete.
Print the warning message, but suppress actual shutdown.
Execute halt or reboot instead of calling init. Passing -n also prevents a file cache flush.
Reboot the system when shutdown is complete.