1 .\" Copyright 1993 Rickard E. Faith (faith@cs.unc.edu)
2 .\" May be distributed under the GNU General Public License
5 dmesg \- print or control the kernel ring buffer
16 is used to examine or control the kernel ring buffer.
18 The program helps users to print out their bootup messages. Instead of
19 copying the messages by hand, the user need only:
25 file to whoever can debug their problem.
29 Clear the ring buffer contents after printing.
32 Print the raw message buffer, i.e., don't strip the log level prefixes.
37 to query the kernel ring buffer. This is 16392 by default.
38 (The default kernel syslog buffer size was 4096
39 at first, 8192 since 1.3.54, 16384 since 2.1.113.)
40 If you have set the kernel buffer to be larger than the default
41 then this option can be used to view the entire buffer.
46 at which logging of messages is done to the console. For example,
48 prevents all messages, expect panic messages, from appearing on the
49 console. All levels of messages are still written to
53 can still be used to control exactly where kernel messages appear. When
60 print or clear the kernel ring buffer.
62 When both options are used, only the last option on the command line will
67 .\" Theodore Ts'o (tytso@athena.mit.edu)
69 The dmesg command is part of the util-linux-ng package and is available from
70 ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.