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SHUTDOWN(8)                Linux Programmer's Manual               SHUTDOWN(8)



NAME
       shutdown(2,8) - close(2,7,n) down the system

SYNOPSIS
       shutdown(2,8) [ -h | -r ] [ -fqs ] [ now | hh:ss | +mins ] [ message ]
       reboot [ -h | -r ] [ -fqs ] [ now | hh:ss | +mins ] [ message ]
       fastboot [ -h | -r ] [ -fqs ] [ now | hh:ss | +mins ] [ message ]
       halt [ -h | -r ] [ -fqs ] [ now | hh:ss | +mins ] [ message ]
       fasthalt [ -h | -r ] [ -fqs ] [ now | hh:ss | +mins ] [ message ]

DESCRIPTION
       In general, shutdown(2,8) prepares the system for a power down or reboot.  A
       absolute or delta time(1,2,n) can be given, and periodic messages will be sent
       to all users(1,5) warning of the shutdown. If no message is specified on the
       command line, shutdown(2,8) will ask for a message to be sent, unless the -q
       option is set.

       halt is the same as shutdown(2,8) -h -q now

       fasthalt is the same as shutdown(2,8) -h -q -f now

       reboot is the same as shutdown(2,8) -r -q now

       fastboot is the same as shutdown(2,8) -r -q -f now

       The default delta time(1,2,n), if(3,n) none is specified, is 2 minutes.

       Five  minutes before shutdown(2,8) (or immediately, if(3,n) shutdown(2,8) is less(1,3) than
       five minutes away), the /etc/nologin file(1,n) is  created  with  a  message
       stating  that  the  system  is going down and that logins are no longer
       permitted.  The login(1,3,5) (1) program  will  not  allow  non-superusers  to
       login(1,3,5)  during this period.  A message will be sent to all users(1,5) at this
       time.

       When the shutdown(2,8) time(1,2,n) arrives,  shutdown(2,8)  notifies  all  users(1,5),  tells
       init(8) not to spawn more getty(8)'s, writes the shutdown(2,8) time(1,2,n) into the
       /var/log/wtmp file(1,n), kills all other processes on the system, sync(1,2,8)(2)'s,
       unmounts  all  the disks, sync(1,2,8)(2)'s again, waits for a second, and then
       either terminates or reboots the system.

       Prior to unmounting all discs, the SIGQUIT signal(2,7) is sent to  the  init
       process,  which  will  in(1,8)  turn exec(3,n,1 builtins) shutdown(2,8)(8). This allows for clean
       unmounting, even if(3,n) the old inode for the init process was unlinked. If
       the current process ID (PID) equals 1, then shutdown(2,8)(8) will pause for-
       ever.

OPTIONS
       -h     Halt the system.  Do not reboot.  This option is used when  pow-
              ering down the system.

       -r     Reboot the system.

       -f     Fast.  When the system is rebooted, the file(1,n) systems will not be
              checked.  This is arranged by creating /fastboot, which  /etc/rc
              must detect (and delete).

       -q     Quiet.   This  uses  a  default  broadcast message, and does not
              prompt the user for one.

       -s     Reboot in(1,8) single  user  mode.   This  is  arranged  by  creating
              /etc/singleboot, which simpleinit(8) detects (and deletes).

FILES
       /etc/rc
       /fastboot
       /etc/singleboot
       /etc/nologin
       /var/log/wtmp
       /etc/shutdown.conf

CONFIG
       The  configuration  file(1,n)  /etc/shutdown.conf  is  used to determine the
       action to take when halting the machine. The currently  supported  file(1,n)
       format  is extremely primitive. The first line must contain two strings
       separated by whitespace. The first string(3,n) must be HALT_ACTION  and  the
       second  specifies  the  action  you  wish  to take on halt. The options
       allowed are:

       halt   This will simply halt the system. This is the default behaviour.
              Note also that this is the fallback if(3,n) another option fails.

       power_off
              This  will  use the kernel power shutdown(2,8) facility. This is usu-
              ally only available on machines with Advanced  Power  Management
              (APM).

       programname
              This  specifies  a  command  to  run to shut down the power. The
              first character must be a "/". Bear in(1,8) mind  that  this  command
              will  be  run with only the root filesystem mounted (and it will
              be read-only), and no daemons running.

SEE ALSO
       umount(8), login(1,3,5)(1), reboot(2), simpleinit(8), init(8)

BUGS
       Unlike the BSD shutdown(2,8), users(1,5) are notified of shutdown(2,8)  only  once  or
       twice,  instead  of many times, and at shorter and shorter intervals as
       "apocalypse approaches."  Some would construe this as a feature.

AUTHOR
       This page documents the version(1,3,5) of shutdown(2,8) originally written by Peter
       Orbaek (poe@daimi.aau.dk).



Linux 2.0                        2 March 2000                      SHUTDOWN(8)

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