BSD 4_2 development
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1.TH DMESG 8 "4 February 1983"
2.UC 4
3.SH NAME
4dmesg \- collect system diagnostic messages to form error log
5.SH SYNOPSIS
6.B /etc/dmesg
7[ \- ]
8.SH DESCRIPTION
9.I Dmesg
10looks in a system buffer for recently printed diagnostic messages
11and prints them on the standard output.
12The messages are those printed by the system when device (hardware) errors
13occur and (occasionally) when system tables overflow non-fatally.
14If the
15.B \-
16flag is given, then
17.I dmesg
18computes (incrementally) the new messages since the last time it
19was run and places these on the standard output.
20This is typically used with
21.IR cron (8)
22to produce the error log
23.I /usr/adm/messages
24by running the command
25.IP
26/etc/dmesg \- >> /usr/adm/messages
27.LP
28every 10 minutes.
29.SH FILES
30.ta 2i
31/usr/adm/messages error log (conventional location)
32.br
33/usr/adm/msgbuf scratch file for memory of \- option
34.SH BUGS
35The system error message buffer is of small finite size. As
36.I dmesg
37is run only every few minutes, not all error messages
38are guaranteed to be logged. This can be construed as a blessing rather
39than a curse.
40.PP
41Error diagnostics generated immediately before a system crash will
42never get logged.