sysvinit/man/halt.8
Jesse 644ee05aab Update manual pages with markup and spacing fixes.
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Updated inittab manual page to include overview of symbols which trigger
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2022-02-15 17:01:41 -04:00

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'\" -*- coding: UTF-8 -*-
.\" Copyright (C) 1998-2001 Miquel van Smoorenburg.
.\"
.\" This program is free software; you can redistribute it and/or modify
.\" it under the terms of the GNU General Public License as published by
.\" the Free Software Foundation; either version 2 of the License, or
.\" (at your option) any later version.
.\"
.\" This program is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
.\" GNU General Public License for more details.
.\"
.\" You should have received a copy of the GNU General Public License
.\" along with this program; if not, write to the Free Software
.\" Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
.\"
.\"{{{}}}
.\"{{{ Title
.TH HALT 8 "Nov 6, 2001" "sysvinit " "Linux System Administrator's Manual"
.\"}}}
.\"{{{ Name
.SH NAME
halt, reboot, poweroff \- stop the system
.\"}}}
.\"{{{ Synopsis
.SH SYNOPSIS
.B /sbin/halt
.RB [ \-n ]
.RB [ \-w ]
.RB [ \-d ]
.RB [ \-f ]
.RB [ \-i ]
.RB [ \-p ]
.RB [ \-h ]
.br
.B /sbin/reboot
.RB [ \-n ]
.RB [ \-w ]
.RB [ \-d ]
.RB [ \-f ]
.RB [ \-i ]
.br
.B /sbin/poweroff
.RB [ \-n ]
.RB [ \-w ]
.RB [ \-d ]
.RB [ \-f ]
.RB [ \-i ]
.RB [ \-h ]
.\"}}}
.\"{{{ Description
.SH DESCRIPTION
\fBhalt\fP notes that the system is being brought down in the file
\fI/var/log/wtmp\fP, and then either tells the kernel to halt, reboot or
power-off the system.
.PP
If \fBhalt\fP or \fBreboot\fP is called when the system is
\fInot\fP in runlevel \fB0\fP or \fB6\fP, in other words when it's running
normally, \fBshutdown\fP will be invoked instead (with the \fB-h\fP
or \fB-r\fP flag). For more info see the \fBshutdown\fP(8)
manpage.
.PP
The rest of this manpage describes the behavior in runlevels 0
and 6, that is when the systems shutdown scripts are being run.
.\"}}}
.\"{{{ Options
.SH OPTIONS
.IP \fB\-n\fP
Don't sync before reboot or halt. Note that the kernel and storage
drivers may still sync. This implies \fB\-d\fP.
.IP \fB\-w\fP
Don't actually reboot or halt but only write the wtmp record
(in the \fI/var/log/wtmp\fP file).
.IP \fB\-d\fP
Don't write the wtmp record.
.IP \fB\-f\fP
Force halt or reboot, don't call \fBshutdown\fP(8).
.IP \fB\-i\fP
Shut down all network interfaces just before \fBhalt\fR or \fBreboot\fR.
Warning: This may not work on interfaces which do not have an IP address
and should ideally be handled by a network manager service.
.IP \fB\-h\fP
Put all hard drives on the system in stand-by mode just before halt or power-off.
.IP \fB\-p\fP
When halting the system, switch off the power. This is the default when \fBhalt\fR is
called as \fBpoweroff\fP.
.\"}}}
.\"{{{ Diagnostics
.SH DIAGNOSTICS
If you're not the superuser, you will get the message `must be superuser'.
.\"}}}
.\"{{{ Notes
.SH NOTES
Under older \fBsysvinit\fP releases, \fBreboot\fP and \fBhalt\fP should
never be called directly. From release 2.74 on \fBhalt\fP and \fBreboot\fP
invoke \fBshutdown\fP(8) if the system is not in runlevel 0 or 6. This
means that if \fBhalt\fP or \fBreboot\fP cannot find out the current
runlevel (for example, when \fI/var/run/utmp\fP hasn't been initialized
correctly and \fI/var/run/runlevel\fR does not exist) \fBshutdown\fP will be called,
which might not be what you want.
Use the \fB-f\fP flag if you want to do a hard \fBhalt\fP or \fBreboot\fP.
.PP
The \fB-h\fP flag puts all hard disks in standby mode just before halt
or power-off. Right now this is only implemented for IDE drives. A side
effect of putting the drive in stand-by 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 power-off.
.PP
The \fBhalt\fP program uses \fI/proc/ide/hd*\fR to find all IDE disk devices,
which means that \fI/proc\fP needs to be mounted when \fBhalt\fP or
\fBpoweroff\fP is called or the \fB-h\fP switch will do nothing.
.PP
.\"}}}
.\"{{{ Author
.SH AUTHOR
.MT miquels@\:cistron\:.nl
Miquel van Smoorenburg
.ME
.\"}}}
.\"{{{ See also
.SH "SEE ALSO"
.BR shutdown (8),
.BR init (8)
.\"}}}