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dmesg - Unix, Linux Command
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
Tag | Description |
-c |
Clear the ring buffer contents after printing.
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-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.
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-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.
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SEE ALSO
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