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  by default.  (The default  kernel

              syslog  buffer  size  was   at first,  since 1.3.,  since 2.1..)  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  prevents  all  messages,

              except panic messages, from appearing on the console.  All levels of messages are still written to /proc/kmsg,

              so syslogd() 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()