*BASH User Commands Ubuntu 10.04.4 LTS Server coreutils
shutdown(8)                                                        shutdown(8)

       shutdown - bring the system down

       shutdown [OPTION]...  TIME [MESSAGE]

       shutdown arranges for the system to be brought down in a safe way.  All
       logged-in users are notified that the system is going down and,  within
       the last five minutes of TIME, new logins are prevented.

       TIME  may  have  different  formats, the most common is simply the word
       'now' which will bring the system down immediately.  Other  valid  for-
       mats  are  +m,  where m is the number of minutes to wait until shutting
       down and hh:mm which specifies the time on the 24hr clock.

       Once TIME has elapsed, shutdown sends a request to the  init(8)  daemon
       to bring the system down into the appropriate runlevel.

       This is performed by emitting the runlevel(7) event, which includes the
       new runlevel in the RUNLEVEL environment variable as well as the previ-
       ous  runlevel  (obtained from the environment or from /var/run/utmp) in
       the PREVLEVEL variable.  An additional INIT_HALT variable may  be  set,
       this will contain the value HALT when bringing the system down for halt
       and POWEROFF when bringing the system down for power off.

       -r     Requests that the system be rebooted after it has  been  brought

       -h     Requests  that  the system be either halted or powered off after
              it has been brought down, with the choice as to which left up to
              the system.

       -H     Requests  that  the  system  be halted after it has been brought

       -P     Requests that the system  be  powered  off  after  it  has  been
              brought down.

       -c     Cancels  a  running  shutdown.   TIME is not specified with this
              option, the first argument is MESSAGE.

       -k     Only send out the warning messages and disable  logins,  do  not
              actually bring the system down.

              shutdown  will  read  the current runlevel from this environment
              variable if set in preference to reading from /var/run/utmp

              Where the current runlevel will be read  from;  this  file  will
              also be updated with the new runlevel.

              A  new runlevel record will be appended to this file for the new

       The Upstart init(8) daemon does not keep  track  of  runlevels  itself,
       instead they are implemented entirely by its userspace tools.

       See runlevel(7) for more details.

       Written by Scott James Remnant <scott@netsplit.com>

       Report bugs at <https://launchpad.net/upstart/+bugs>

       Copyright (C) 2009 Canonical Ltd.
       This is free software; see the source for copying conditions.  There is
       NO warranty; not even for MERCHANTABILITY or FITNESS FOR  A  PARTICULAR

       runlevel(7) init(8) telinit(8) reboot(8)

Upstart                           2009-07-09                       shutdown(8)