Flashnux

GNU/Linux man pages

GNU/Linux

RedHat 6.2

(Zoot)

dmesg(8)


DMESG

DMESG

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
SEE ALSO
AUTHOR

NAME

dmesg − print or control the kernel ring buffer

SYNOPSIS

dmesg [ −c ] [ −n level ] [ −s bufsize ]

DESCRIPTION

dmesg is used to examine or control the kernel ring buffer.

The program helps users to print out their bootup messages. Instead of copying the messages by hand, the user need only:

dmesg > boot.messages

and mail the boot.messages file to whoever can debug their problem.

OPTIONS

−c

clear the ring buffer contents after printing.

−sbufsize

use a buffer of bufsize to query the kernel ring buffer. This is 8196 by default (this matches the default kernel syslog buffer size in 2.0.33 and 2.1.103). If you have set the kernel buffer to larger than the default then this option can be used to view the entire buffer.

−nlevel

set the level at which logging of messages is done to the console. For example, −n 1 prevents all messages, expect panic messages, from appearing on the console. All levels of messages are still written to /proc/kmsg, so syslogd(8) can still be used to control exactly where kernel messages appear. When the −n option is used, dmesg will not print or clear the kernel ring buffer.

When both options are used, only the last option on the command line will have an effect.

SEE ALSO

syslogd(8)

AUTHOR

Theodore Ts’o (tytso@athena.mit.edu)



dmesg(8)