freebsd-dev/sbin/dmesg/dmesg.8

.\" Copyright (c) 1980, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
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.\"     @(#)dmesg.8	8.1 (Berkeley) 6/5/93
.\" $FreeBSD$
.\"
.Dd October 3, 2016
.Dt DMESG 8
.Os
.Sh NAME
.Nm dmesg
.Nd "display the system message buffer"
.Sh SYNOPSIS
.Nm
.Op Fl ac
.Op Fl M Ar core Op Fl N Ar system
.Sh DESCRIPTION
The
.Nm
utility displays the contents of the system message buffer.
If the
.Fl M
option is not specified, the buffer is read from the currently running kernel
via the
.Xr sysctl 3
interface.
Otherwise, the buffer is read from the specified core file,
using the name list from the specified kernel image (or from
the default image).
.Pp
The options are as follows:
.Bl -tag -width indent
.It Fl a
Show all data in the message buffer.
This includes any syslog records and
.Pa /dev/console
output.
.It Fl c
Clear the kernel buffer after printing.
.It Fl M
Extract values associated with the name list from the specified core.
.It Fl N
If
.Fl M
is also specified,
extract the name list from the specified system instead of the default,
which is the kernel image the system has booted from.
.El
.Sh FILES
.Bl -tag -width ".Pa /var/run/dmesg.boot" -compact
.It Pa /var/run/dmesg.boot
usually a snapshot of the buffer contents
taken soon after file systems are mounted
at startup time
.El
.Sh SEE ALSO
.Xr sysctl 3 ,
.Xr syslogd 8
.Sh HISTORY
The
.Nm
utility appeared in
.Bx 3 .
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`.\" Copyright (c) 1980, 1991, 1993`
			`.\" The Regents of the University of California. All rights reserved.`
			`.\"`
			`.\" Redistribution and use in source and binary forms, with or without`
			`.\" modification, are permitted provided that the following conditions`
			`.\" are met:`
			`.\" 1. Redistributions of source code must retain the above copyright`
			`.\" notice, this list of conditions and the following disclaimer.`
			`.\" 2. Redistributions in binary form must reproduce the above copyright`
			`.\" notice, this list of conditions and the following disclaimer in the`
			`.\" documentation and/or other materials provided with the distribution.`
Renumber copyright clause 4 Renumber cluase 4 to 3, per what everybody else did when BSD granted them permission to remove clause 3. My insistance on keeping the same numbering for legal reasons is too pedantic, so give up on that point. Submitted by: Jan Schaumann <jschauma@stevens.edu> Pull Request: https://github.com/freebsd/freebsd/pull/96 2017-02-28 23:42:47 +00:00			`.\" 3. Neither the name of the University nor the names of its contributors`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`.\" may be used to endorse or promote products derived from this software`
			`.\" without specific prior written permission.`
			`.\"`
			.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
			`.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE`
			`.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE`
			`.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE`
			`.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL`
			`.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS`
			`.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)`
			`.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT`
			`.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY`
			`.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF`
			`.\" SUCH DAMAGE.`
			`.\"`
			`.\" @(#)dmesg.8 8.1 (Berkeley) 6/5/93`
$Id$ -> $FreeBSD$ 1999-08-28 00:22:10 +00:00			`.\" $FreeBSD$`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`.\"`
dmesg(8) first appeared in 3BSD. http://minnie.tuhs.org/cgi-bin/utree.pl?file=3BSD/usr/man/man1/dmesg.1m PR: 212443 Approved by: bcr (mentor) Obtained from: TUHS MFC after: 4 days Differential Revision: https://reviews.freebsd.org/D8105 2016-10-02 23:26:41 +00:00			`.Dd October 3, 2016`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`.Dt DMESG 8`
mdoc(7) police: removed HISTORY info from the .Os call. 2001-07-10 11:04:34 +00:00			`.Os`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`.Sh NAME`
			`.Nm dmesg`
			`.Nd "display the system message buffer"`
			`.Sh SYNOPSIS`
mdoc(7) police: use the new features of the Nm macro. 2000-11-20 16:52:27 +00:00			`.Nm`
Add support for 'dmesg -c' which clears the dmesg buffer after it has been printed. This provides compatibility with other *nix systems (including Linux). While here use stdbool booleans for 'all'. PR: bin/178295 Submitted by: Levent Serinol <lserinol@gmail.com> Reviewed by: will 2013-05-10 03:42:48 +00:00			`.Op Fl ac`
Not too much point specifying -N but not specifying -M. 2004-03-26 09:24:45 +00:00			`.Op Fl M Ar core Op Fl N Ar system`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`.Sh DESCRIPTION`
The .Nm utility 2002-07-06 19:34:18 +00:00			`The`
			`.Nm`
			`utility displays the contents of the system message buffer.`
Not too much point specifying -N but not specifying -M. 2004-03-26 09:24:45 +00:00			`If the`
Update the dmesg man page to reflect the recent changes to dmesg. Reviewed by: ru 2001-07-05 12:32:57 +00:00			`.Fl M`
Not too much point specifying -N but not specifying -M. 2004-03-26 09:24:45 +00:00			`option is not specified, the buffer is read from the currently running kernel`
Update the dmesg man page to reflect the recent changes to dmesg. Reviewed by: ru 2001-07-05 12:32:57 +00:00			`via the`
			`.Xr sysctl 3`
			`interface.`
Not too much point specifying -N but not specifying -M. 2004-03-26 09:24:45 +00:00			`Otherwise, the buffer is read from the specified core file,`
			`using the name list from the specified kernel image (or from`
Update the dmesg man page to reflect the recent changes to dmesg. Reviewed by: ru 2001-07-05 12:32:57 +00:00			`the default image).`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`.Pp`
			`The options are as follows:`
Use .Pa for filenames. Use .Bl/.El in FILES section. Remove unused #includes. 1998-06-04 06:51:14 +00:00			`.Bl -tag -width indent`
Add a -a option to show the entire message buffer. 2000-12-17 19:05:17 +00:00			`.It Fl a`
Fix hard sentence break introduced in previous commit. 2000-12-20 13:23:50 +00:00			`Show all data in the message buffer.`
			`This includes any syslog records and`
Add a -a option to show the entire message buffer. 2000-12-17 19:05:17 +00:00			`.Pa /dev/console`
			`output.`
Add support for 'dmesg -c' which clears the dmesg buffer after it has been printed. This provides compatibility with other *nix systems (including Linux). While here use stdbool booleans for 'all'. PR: bin/178295 Submitted by: Levent Serinol <lserinol@gmail.com> Reviewed by: will 2013-05-10 03:42:48 +00:00			`.It Fl c`
			`Clear the kernel buffer after printing.`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`.It Fl M`
Not too much point specifying -N but not specifying -M. 2004-03-26 09:24:45 +00:00			`Extract values associated with the name list from the specified core.`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`.It Fl N`
Not too much point specifying -N but not specifying -M. 2004-03-26 09:24:45 +00:00			`If`
			`.Fl M`
			`is also specified,`
			`extract the name list from the specified system instead of the default,`
Update the dmesg man page to reflect the recent changes to dmesg. Reviewed by: ru 2001-07-05 12:32:57 +00:00			`which is the kernel image the system has booted from.`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`.El`
Add mention of /var/run/dmesg.boot. Yes, this isn't really the right place for it. No, it really can't remain undocumented. 2001-08-08 21:02:55 +00:00			`.Sh FILES`
mdoc(7) police: compute the exact tag width. 2001-08-10 10:09:00 +00:00			`.Bl -tag -width ".Pa /var/run/dmesg.boot" -compact`
Add mention of /var/run/dmesg.boot. Yes, this isn't really the right place for it. No, it really can't remain undocumented. 2001-08-08 21:02:55 +00:00			`.It Pa /var/run/dmesg.boot`
			`usually a snapshot of the buffer contents`
s/filesystem/file system/g as discussed on -developers 2002-08-21 18:11:48 +00:00			`taken soon after file systems are mounted`
Add mention of /var/run/dmesg.boot. Yes, this isn't really the right place for it. No, it really can't remain undocumented. 2001-08-08 21:02:55 +00:00			`at startup time`
			`.El`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`.Sh SEE ALSO`
Update the dmesg man page to reflect the recent changes to dmesg. Reviewed by: ru 2001-07-05 12:32:57 +00:00			`.Xr sysctl 3 ,`
BSD 4.4 Lite sbin Sources Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin. 1994-05-26 06:35:07 +00:00			`.Xr syslogd 8`
			`.Sh HISTORY`
			`The`
			`.Nm`
The .Nm utility 2002-07-06 19:34:18 +00:00			`utility appeared in`
dmesg(8) first appeared in 3BSD. http://minnie.tuhs.org/cgi-bin/utree.pl?file=3BSD/usr/man/man1/dmesg.1m PR: 212443 Approved by: bcr (mentor) Obtained from: TUHS MFC after: 4 days Differential Revision: https://reviews.freebsd.org/D8105 2016-10-02 23:26:41 +00:00			`.Bx 3 .`