dmesg

dmesg: print the kernel’s log.

Synopsis

dmesg [-w] [-c | -C]

Description

dmesg prints the kernel’s log, oldest first: devices joining and leaving the bus, each event the kernel takes from a device (a motion, a key, a frame), mounts, a process that crashed (past its own error handler: a program’s error is reported by the program, as an exit), and the kernel’s own messages. It keeps the last 200.

Each line is an entry, as OpenOS’s dmesg showed events: the time by the world’s clock, in brackets; where it came from (a device’s name as lsdev(1) gives it, or mount, kernel, a process as its path and pid); the device’s id; and what happened. On a terminal they’re in color, OpenOS’s: the time red, where green, the id yellow.

Options

-w, –follow

Waits for more, printing each entry as it comes, until ^C.

-c

Clears the log after printing it.

-C

Clears the log, printing nothing.

Exit status

0; 1 for an option it does not know.

Examples

dmesg
dmesg -w
dmesg | grep storage

Notes

Linux’s dmesg shows seconds since boot and the kernel’s subsystems’ messages; mcos’s shows the world’s time, and the devices’ events as OpenOS’s did.

See also

lsdev(1)