.\"	$OpenBSD: dmesg.8,v 1.18 2024/06/30 23:44:49 jsg Exp $
.\"	$NetBSD: dmesg.8,v 1.9 1995/03/18 14:54:47 cgd Exp $
.\"
.\" 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.
.\"
.\"     @(#)dmesg.8	8.1 (Berkeley) 6/5/93
.\"
.Dd $Mdocdate: June 30 2024 $
.Dt DMESG 8
.Os
.Sh NAME
.Nm dmesg
.Nd display the system message buffer
.Sh SYNOPSIS
.Nm dmesg
.Op Fl s
.Op Fl M Ar core
.Op Fl N Ar system
.Sh DESCRIPTION
.Nm
displays the contents of the system message buffer.
It is most commonly used to review system startup messages.
On some systems the message buffer can survive reboot and be
retained (in the hope of exposing information from a crash).
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl M Ar core
Extract values associated with the name list from the specified
.Ar core
instead of the default
.Pa /dev/kmem .
.It Fl N Ar system
Extract the name list from the specified
.Ar system
instead of the default
.Pa /bsd .
.It Fl s
Display the contents of the console message buffer instead.
This can be used to review
.Xr rc 8
system startup messages.
This option is limited to the superuser.
.El
.Sh FILES
.Bl -tag -width /var/run/dmesg.boot -compact
.It Pa /var/run/dmesg.boot
copy of
.Nm
saved by
.Xr rc 8
at boot time
.El
.Sh SEE ALSO
.Xr syslogd 8
.Sh HISTORY
The
.Nm
command appeared in
.At v7 .