format changes and other fixes
[unix-history] / usr / src / sbin / dmesg / dmesg.8
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1da6d6c3
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1.\" Copyright (c) 1980 Regents of the University of California.
2.\" All rights reserved. The Berkeley software License Agreement
3.\" specifies the terms and conditions for redistribution.
4.\"
d6a30cad 5.\" @(#)dmesg.8 6.1 (Berkeley) %G%
1da6d6c3 6.\"
d6a30cad 7.TH DMESG 8 ""
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8.UC 4
9.SH NAME
10dmesg \- collect system diagnostic messages to form error log
11.SH SYNOPSIS
12.B /etc/dmesg
13[ \- ]
14.SH DESCRIPTION
15.I Dmesg
16looks in a system buffer for recently printed diagnostic messages
17and prints them on the standard output.
18The messages are those printed by the system when device (hardware) errors
19occur and (occasionally) when system tables overflow non-fatally.
20If the
21.B \-
22flag is given, then
23.I dmesg
24computes (incrementally) the new messages since the last time it
25was run and places these on the standard output.
26This is typically used with
27.IR cron (8)
28to produce the error log
29.I /usr/adm/messages
30by running the command
31.IP
32/etc/dmesg \- >> /usr/adm/messages
33.LP
34every 10 minutes.
35.SH FILES
36.ta 2i
37/usr/adm/messages error log (conventional location)
38.br
39/usr/adm/msgbuf scratch file for memory of \- option
40.SH BUGS
41The system error message buffer is of small finite size. As
42.I dmesg
43is run only every few minutes, not all error messages
44are guaranteed to be logged. This can be construed as a blessing rather
45than a curse.
46.PP
47Error diagnostics generated immediately before a system crash will
48never get logged.