120 lines
3.9 KiB
Groff
120 lines
3.9 KiB
Groff
.\" $NetBSD: reboot.8,v 1.21 2003/08/07 10:04:37 agc Exp $
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.\"
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.\" Copyright (c) 1990, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)reboot.8 8.1 (Berkeley) 6/9/93
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.\"
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.Dd April 4, 2003
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.Dt REBOOT 8
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.Os
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.Sh NAME
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.Nm reboot ,
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.Nm poweroff ,
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.Nm halt
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.Nd restarting, powering down and stopping the system
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.Sh SYNOPSIS
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.Nm halt
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.Op Fl dlnpq
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.Nm poweroff
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.Op Fl dlnq
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.Nm
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.Op Fl dlnq
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.Sh DESCRIPTION
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The
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.Nm poweroff ,
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.Nm halt
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and
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.Nm
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utilities flush the file system cache to disk, send all running processes
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a SIGTERM, wait for several seconds for them to die, send a SIGKILL to the
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survivors and, respectively, power down, halt or restart the system.
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The action is logged, including entering a shutdown record into the login
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accounting file and sending a message via
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.Xr syslog 3 .
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.Pp
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The options are as follows:
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.Bl -tag -width Ds
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.It Fl d
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Create a dump before halting or restarting.
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This option is useful for debugging system dump procedures or
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capturing the state of a corrupted or misbehaving system.
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.It Fl l
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Suppress sending a message via
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.Xr syslog 3
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before halting or restarting.
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.It Fl n
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Do not flush the file system cache.
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This option should be used with extreme caution.
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It can be used if a disk or the processor is on fire.
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.It Fl p
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Attempt to powerdown the system.
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If the powerdown fails, or the system does not support
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software powerdown, the system will halt.
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This option is only valid for
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.Nm halt .
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.It Fl q
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Do not give processes a chance to shut down before halting or restarting.
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This option should not normally be used.
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.El
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.Pp
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Normally, the
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.Xr shutdown 8
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utility is used when the system needs to be halted or restarted, giving
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users advance warning of their impending doom.
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.Sh SEE ALSO
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.Xr reboot 2 ,
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.Xr syslog 3 ,
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.Xr utmp 5 ,
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.Xr boot 8 ,
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.Xr shutdown 8 ,
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.Xr sync 8
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.Sh HISTORY
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A
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.Nm
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command appeared in
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.At v6 .
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.Pp
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The
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.Nm poweroff
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command first appeared in
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.Nx 1.5 .
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.Sh CAVEATS
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Once the command has begun its work, stopping it before it completes
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will probably result in a system so crippled it must be
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physically reset.
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To prevent premature termination, the command
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blocks many signals early in its execution.
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However, nothing can defend against deliberate attempts to evade this.
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.Sh BUGS
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The single user shell will ignore the SIGTERM signal.
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To avoid waiting for the timeout when
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rebooting or halting from the single user shell, you have to
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.Ic exec reboot
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or
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.Ic exec halt .
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