DMESG - phpMan

DMESG(8) DMESG(8)

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 size bufsize to query the kernel ring buffer. This is 16392
by default. (The default kernel syslog buffer size was 4096 at first, 8192
since 1.3.54, 16384 since 2.1.113.) If you have set the kernel buffer to be
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 ker-
nel ring buffer.

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