reboot



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)

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