Provided by: util-linux_2.17.2-0ubuntu1_i386 bug

NAME

       dmesg - print or control the kernel ring buffer

SYNOPSIS

       dmesg [-c] [-r] [-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.

       -r     Print the raw message buffer, i.e., don’t strip  the  log  level
              prefixes.

       -s bufsize
              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.

       -n level
              Set  the  level  at  which  logging  of  messages is done to the
              console.  For example, -n 1 prevents all messages, except  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)

AVAILABILITY

       The dmesg command is part of the util-linux-ng package and is available
       from ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.

                                                                      DMESG(1)