HALT(8)               Linux System Administrator`s Manual            HALT(8)



NAME
       halt, reboot, poweroff - stop the system.

SYNOPSIS
       /sbin/halt [-n] [-w] [-d] [-f] [-i] [-p] [-h]
       /sbin/reboot [-n] [-w] [-d] [-f] [-i]
       /sbin/poweroff [-n] [-w] [-d] [-f] [-i] [-h]

DESCRIPTION
       Halt  notes  that  the  system  is  being  brought  down  in  the  file
       /var/log/wtmp, and then either tells the  kernel  to  halt,  reboot  or
       poweroff the system.

       If  halt or reboot is called when the system is not in runlevel 0 or 6,
       in other words when it`s running normally,  shutdown  will  be  invoked
       instead  (with  the  -h  or -r flag). For more info see the shutdown(8)
       manpage.

       The rest of this manpage describes the behaviour in runlevels 0 and  6,
       that is when the systems shutdown scripts are being run.

OPTIONS
       -n     Don`t sync before reboot or halt.

       -w     Don`t actually reboot or halt but only write the wtmp record (in
              the /var/log/wtmp file).

       -d     Don`t write the wtmp record. The -n flag implies -d.

       -f     Force halt or reboot, don`t call shutdown(8).

       -i     Shut down all network interfaces just before halt or reboot.

       -h     Put all harddrives on the system in  standby  mode  just  before
              halt or poweroff.

       -p     When halting the system, do a poweroff. This is the default when
              halt is called as poweroff.

DIAGNOSTICS
       If you`re not the superuser, you will get the message  `must  be      supe-
       ruser`.

NOTES
       Under  older sysvinit releases , reboot and halt should never be called
       directly. From release 2.74 on halt and reboot  invoke  shutdown(8)  if
       the system is not in runlevel 0 or 6. This means that if halt or reboot
       cannot find out the current runlevel (for example,  when  /var/run/utmp
       hasn`t been initialized correctly) shutdown will be called, which might
       not be what you want.  Use the -f flag if you want to do a hard halt or
       reboot.

       The  -h  flag  puts  all  harddisks in standby mode just before halt or
       poweroff. Right now this is only implemented for  IDE  drives.  A  side
       effect  of putting the drive in standby mode is that the write cache on
       the disk is flushed. This is important for IDE drives, since the kernel
       doesn`t flush the write-cache itself before poweroff.

       The halt program uses /proc/ide/hd* to find all IDE disk devices, which
       means that /proc needs to be mounted when halt or poweroff is called or
       the -h switch will do nothing.


AUTHOR
       Miquel van Smoorenburg, miquels@cistron.nl

SEE ALSO
       shutdown(8), init(8)



                                  Nov 6, 2001                          HALT(8)