shutdown

Close down the system at a given time.
Shutdown provides an automated shutdown procedure for super-users to nicely notify users when the system is shutting down, saving them from system administrators, hackers, and gurus, who would otherwise not bother with such niceties.

SYNTAX
      shutdown [-] [-fhkrn] time [warning-message ...]

Options
     -f    Shutdown arranges, in the manner of fastboot(8),  for the file sys-
           tems not to be checked on reboot.

     -h    The system is halted at the specified time when shutdown execs
           halt(8).

     -k    Kick every body off.  The -k option does not actually halt the sys-
           tem, but leaves the system multi-user with logins disabled (for all
           but super-user).

     -n    Prevent the normal sync(2) before stopping.

     -r    Shutdown execs reboot(8) at the specified time.

     time  Time is the time at which shutdown will bring the system down and
           may be the word now (indicating an immediate shutdown) or specify a
           future time in one of two formats: +number, or yymmddhhmm, where
           the year, month, and day may be defaulted to the current system
           values.  The first form brings the system down in number minutes
           and the second at the absolute time specified.

     warning-message
           Any other arguments comprise the warning message that is broadcast
           to users currently logged into the system.

     -     If `-' is supplied as an option, the warning message is read from
           the standard input.

Example
    shutdown -h now We are going to shut the computer down right now.

Notes
At intervals, becoming more frequent as apocalypse approaches and starting at ten hours before shutdown, warning messages are displayed on the terminals of all users logged in.

Five minutes before shutdown, or immediately if shutdown is in less than 5 minutes, logins are disabled by creating /etc/nologin and copying the warning message there. If this file exists when a user attempts to log in, login(1) prints its contents and exits. The file is removed just before shutdown exits.

At shutdown time a message is written in the system log, containing the time of shutdown, who initiated the shutdown and the reason. A terminate signal is then sent to init to bring the system down to single-user state (depending on above options).

The time of the shutdown and the warning message are placed in /etc/nologin and should be used to inform the users about when the system will be back up and why it is going down (or anything else).

The hours and minutes in the second time format may be separated by a colon (``:'') for backward compatibility.

FILES
/etc/nologin tells login not to let anyone log in
/fastboot tells rc(8) not to run fsck when rebooting

"Do all men kill the things they do not love?" ~The Merchant of Venice

Related commands:

login - log into the computer
wall(1)
fastboot(8)
halt(8)
reboot(8)

Equivalent BASH command:

shutdown - Close down the system at a given time.