1.\" $OpenBSD: dmesg.8,v 1.16 2015/03/13 16:15:08 deraadt Exp $ 2.\" $NetBSD: dmesg.8,v 1.9 1995/03/18 14:54:47 cgd Exp $ 3.\" 4.\" Copyright (c) 1980, 1991, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)dmesg.8 8.1 (Berkeley) 6/5/93 32.\" 33.Dd $Mdocdate: March 13 2015 $ 34.Dt DMESG 8 35.Os 36.Sh NAME 37.Nm dmesg 38.Nd display the system message buffer 39.Sh SYNOPSIS 40.Nm dmesg 41.Op Fl s 42.Op Fl M Ar core 43.Op Fl N Ar system 44.Sh DESCRIPTION 45.Nm 46displays the contents of the system message buffer. 47It is most commonly used to review system startup messages. 48On some systems the message buffer can survive reboot and be 49retained (in the hope of exposing information from a crash). 50.Pp 51The options are as follows: 52.Bl -tag -width Ds 53.It Fl M Ar core 54Extract values associated with the name list from the specified 55.Ar core 56instead of the default 57.Pa /dev/kmem . 58.It Fl N Ar system 59Extract the name list from the specified 60.Ar system 61instead of the default 62.Pa /bsd . 63.It Fl s 64Display the contents of the console message buffer instead. 65This can be used to review 66.Xr rc 8 67system startup messages. 68This option is limited to the superuser. 69.El 70.Sh FILES 71.Bl -tag -width /var/run/dmesg.boot -compact 72.It Pa /var/run/dmesg.boot 73copy of 74.Nm 75saved by 76.Xr rc 8 77at boot time 78.El 79.Sh SEE ALSO 80.Xr syslogd 8 81.Sh HISTORY 82The 83.Nm 84command appeared in 85.Bx 4.0 . 86