8c0fa2cc56
Sponsored by: Netflix
197 lines
5.6 KiB
Groff
197 lines
5.6 KiB
Groff
.\" 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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.\" $FreeBSD$
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.\"
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.Dd December 20, 2017
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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 halt ,
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.Nm fastboot ,
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.Nm fasthalt
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.Nd stopping and restarting the system
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.Sh SYNOPSIS
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.Nm halt
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.Op Fl lNnpq
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.Op Fl k Ar kernel
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.Nm
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.Op Fl cdlNnpqr
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.Op Fl k Ar kernel
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.Nm fasthalt
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.Op Fl lNnpq
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.Op Fl k Ar kernel
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.Nm fastboot
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.Op Fl dlNnpq
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.Op Fl k Ar kernel
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.Sh DESCRIPTION
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The
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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
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.Dv SIGTERM
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(and subsequently a
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.Dv SIGKILL )
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and, respectively, halt or restart the system.
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The action is logged, including entering a shutdown record into the user
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accounting database.
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.Pp
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The options are as follows:
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.Bl -tag -width indent
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.It Fl c
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The system will turn off the power and then turn it back on if it can.
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If the power down action fails, the system
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will halt or reboot normally, depending on whether
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.Nm halt
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or
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.Nm
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was called.
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At the present time, only the
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.Xr ipmi 4
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driver implements the power cycle functionality and only on hardware
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with a BMC that supports power cycling.
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Unlike power off, the amount of hardware that supports power cycling
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is small.
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.It Fl d
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The system is requested to create a crash dump.
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This option is
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supported only when rebooting, and it has no effect unless a dump
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device has previously been specified with
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.Xr dumpon 8 .
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.It Fl k Ar kernel
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Boot the specified
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.Ar kernel
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on the next system boot.
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If the kernel boots successfully, the
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.Em default
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kernel will be booted on successive boots, this is a one-shot option.
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If the boot fails, the system will continue attempting to boot
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.Ar kernel
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until the boot process is interrupted and a valid kernel booted.
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This may change in the future.
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.It Fl l
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The halt or reboot is
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.Em not
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logged to the system log.
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This option is intended for applications such as
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.Xr shutdown 8 ,
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that call
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.Nm
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or
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.Nm halt
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and log this themselves.
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.It Fl N
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The file system cache is not flushed during the initial process clean-up,
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however the kernel level
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.Xr reboot 2
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is still processed with a sync.
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This option can be useful for performing a
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.Dq best-effort
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reboot when devices might be unavailable.
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This can happen when devices have been disconnected, such as with
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.Xr iscsi 4 .
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.It Fl n
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The file system cache is not flushed.
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This option should probably not be used.
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.It Fl p
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The system will turn off the power if it can.
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If the power down action fails, the system
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will halt or reboot normally, depending on whether
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.Nm halt
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or
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.Nm
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was called.
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.It Fl q
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The system is halted or restarted quickly and ungracefully, and only
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the flushing of the file system cache is performed (if the
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.Fl n
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option is not specified).
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This option should probably not be used.
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.It Fl r
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The system kills all processes, unmounts all filesystems, mounts the new
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root filesystem, and begins the usual startup sequence.
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After changing vfs.root.mountfrom with
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.Xr kenv 1 ,
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.Nm Fl r
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can be used to change the root filesystem while preserving kernel state.
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This requires the
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.Xr tmpfs 5
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kernel module to be loaded because
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.Xr init 8
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needs a place to store itself after the old root is unmounted, but
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before the new root is in place.
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.El
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.Pp
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The
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.Nm fasthalt
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and
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.Nm fastboot
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utilities are nothing more than aliases for the
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.Nm halt
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and
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.Nm
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utilities.
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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 and cleanly terminating
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specific programs.
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.Sh EXAMPLES
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Replace current root filesystem with UFS mounted from
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.Pa /dev/ada0s1a :
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.Bd -literal -offset indent
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kenv vfs.root.mountfrom=ufs:/dev/ada0s1a
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reboot -r
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.Ed
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.Pp
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This mechanism can also be used with NFS, with a caveat that
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it only works with NFSv4, and requires a numeric IPv4 address:
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.Bd -literal -offset indent
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kenv vfs.root.mountfrom=nfs:192.168.1.1:/share/name
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reboot -r
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.Ed
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.Sh SEE ALSO
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.Xr kenv 1 ,
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.Xr getutxent 3 ,
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.Xr ipmi 4 ,
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.Xr boot 8 ,
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.Xr dumpon 8 ,
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.Xr nextboot 8 ,
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.Xr savecore 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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utility appeared in
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.Bx 4.0 .
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