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 con-
	      sole.  For example, -n 1 prevents all  messages,	expect	panic
	      messages,	 from  appearing  on the console.  All levels of mes-
	      sages 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)

UNIX/Linux commands referenced on this page:

1. users
2. file
3. size
4. at
5. view
6. which
7. clear
8. last