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DMESG(8)               DragonFly System Manager's Manual              DMESG(8)


NAME

     dmesg - display the system message buffer


SYNOPSIS

     dmesg [-a] [-c] [-f[f]] [-M core] [-N system] [-n dumpnr]


DESCRIPTION

     The dmesg utility displays the contents of the system message buffer.  If
     neither the -N nor the -M option is specified, the buffer is read from
     the currently running kernel via the sysctl(3) interface.  Otherwise, the
     buffer is read from the specified core file (or from the default one),
     using the name list from the specified kernel image (or from the default
     image).

     The options are as follows:

     -a      Show all data in the message buffer.  This includes any syslog
             records and /dev/console output.

     -c      Clear the kernel buffer after printing.

     -f[f]   After the initial message buffer dump dmesg monitors the kernel
             for additional data and displays it as it arrives.  dmesg will
             not terminate until killed in this mode.  If this option is
             specified twice, dmesg will live loop (using the CPU heavily) to
             obtain updates as quickly as possible.  This second mode should
             only be used when trying to debug a kernel crashing situation.

     -M core
             Extract values associated with the name list from the specified
             core instead of the default /dev/kmem.

     -N system
             Extract the name list from the specified system instead of the
             default, which is the kernel image the system has booted from.

     -n dumpnr
             Use the kernel core dump file numbered dumpnr for debugging.  If
             not found in the current directory, /var/crash is checked.


FILES

     /var/run/dmesg.boot      usually a snapshot of the buffer contents taken
                              soon after file systems are mounted at startup
                              time


SEE ALSO

     sysctl(3), syslogd(8)


HISTORY

     The dmesg utility appeared in 3.0BSD.

DragonFly 5.9-DEVELOPMENT     September 29, 2016     DragonFly 5.9-DEVELOPMENT

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