204 lines
5.6 KiB
Groff
204 lines
5.6 KiB
Groff
.\" $NetBSD: savecore.8,v 1.37 2012/03/15 22:35:03 njoly Exp $
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.\"
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.\" Copyright (c) 1980, 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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.\" @(#)savecore.8 8.1 (Berkeley) 6/5/93
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.\"
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.Dd September 13, 2011
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.Dt SAVECORE 8
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.Os
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.Sh NAME
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.Nm savecore
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.Nd save a core dump of the operating system
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.Sh SYNOPSIS
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.Nm
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.Op Fl fvz
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.Op Fl N Ar system
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.Op Fl Z Ar level
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.Op Ar directory
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.Nm
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.Fl c
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.Op Fl v
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.Op Fl N Ar system
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.Nm
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.Fl n
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.Op Fl v
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.Op Fl N Ar system
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.Sh DESCRIPTION
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When the
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.Nx
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kernel encounters a fatal error, the
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.Xr panic 9
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routine arranges for a snapshot of the contents of physical memory to
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be written into a dump area, typically in the swap partition.
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.Pp
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Upon a subsequent reboot,
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.Nm
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is typically run out of
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.Xr rc 8 ,
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before swapping is enabled, to copy the kernel and the saved memory image
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into
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.Fa directory ,
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and enters a reboot message and information about the core dump into
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the system log.
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If a directory is not specified, then
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.Pa /var/crash
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is used.
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.Pp
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The kernel and core file can then be analyzed using various tools,
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including
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.Xr crash 8 ,
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.Xr dmesg 8 ,
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.Xr fstat 1 ,
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.Xr gdb 1 ,
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.Xr iostat 8 ,
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.Xr netstat 1 ,
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.Xr ps 1 ,
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and
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.Xr pstat 8 ,
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to attempt to deduce the cause of the crash.
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.Pp
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Crashes are usually the result of hardware faults or kernel bugs.
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If a kernel bug is suspected, a full bug report should be filed at
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.Lk http://www.netbsd.org/ ,
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or using
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.Xr send-pr 1 ,
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containing as much information as possible about the circumstances of
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the crash.
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Since crash dumps are typically very large and may contain
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whatever (potentially confidential) information was in memory at the
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time of the crash, do
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.Em NOT
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include a copy of the crash dump file in the bug report; instead, save it
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somewhere in the event that a
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.Nx
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developer wants to examine it.
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.Pp
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The options are as follows:
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.Bl -tag -width directory
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.It Fl c
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Only clears the dump without saving it, so that future invocations of
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.Nm
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will ignore it.
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.It Fl f
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Forces a dump to be taken even if the dump doesn't appear correct or there
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is insufficient disk space.
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.It Fl n
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Check whether a dump is present without taking further action.
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The command exits with zero status if a dump is present, or with non-zero
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status otherwise.
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.It Fl N
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Use
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.Ar system
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as the kernel instead of the default (returned by
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.Xr getbootfile 3 ) .
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Note that
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.Xr getbootfile 3
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uses
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.Xr secure_path 3
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to check that kernel file is
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.Dq secure
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and will default to
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.Pa /netbsd
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if the check fails.
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.It Fl v
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Prints out some additional debugging information.
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.It Fl z
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Compresses the core dump and kernel (see
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.Xr gzip 1 ) .
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.It Fl Z Ar level
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Set the compression level for
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.Fl z
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to
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.Ar level .
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Defaults to 1 (the fastest compression mode).
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Refer to
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.Xr gzip 1
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for more information regarding the compression level.
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.El
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.Pp
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.Nm
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checks the core dump in various ways to make sure that it is current and
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that it corresponds to the currently running system.
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If it passes these checks, it saves the core image in
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.Ar directory Ns Pa /netbsd.#.core
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and the system in
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.Ar directory Ns Pa /netbsd.#
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(or in
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.Ar directory Ns Pa /netbsd.#.core.gz
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and
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.Ar directory Ns Pa /netbsd.#.gz ,
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respectively, if the
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.Fl z
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option is used).
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The
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.Dq #
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is the number from the first line of the file
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.Ar directory Ns Pa /bounds ,
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and it is incremented and stored back into the file each time
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.Nm
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successfully runs.
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.Pp
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.Nm
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also checks the available disk space before attempting to make the copies.
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If there is insufficient disk space in the file system containing
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.Ar directory ,
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or if the file
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.Ar directory Ns Pa /minfree
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exists and the number of free kilobytes (for non-superusers) in the
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file system after the copies were made would be less than the number
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in the first line of this file, the copies are not attempted.
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.Pp
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If
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.Nm
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successfully copies the kernel and the core dump, the core dump is cleared
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so that future invocations of
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.Nm
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will ignore it.
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.Sh SEE ALSO
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.Xr fstat 1 ,
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.Xr gdb 1 ,
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.Xr gzip 1 ,
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.Xr netstat 1 ,
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.Xr ps 1 ,
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.Xr send-pr 1 ,
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.Xr crash 8 ,
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.Xr dmesg 8 ,
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.Xr iostat 8 ,
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.Xr pstat 8 ,
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.Xr rc 8 ,
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.Xr syslogd 8 ,
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.Xr panic 9
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.Sh HISTORY
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The
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.Nm
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command appeared in
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.Bx 4.1 .
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.Sh BUGS
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The minfree code does not consider the effect of compression.
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