dmesg

Linux · System · reference only

What it does

Shows the kernel message buffer: boot, hardware detection, drivers and system errors.

Syntax

dmesg [opciones]

Options and parameters

• -T

  Shows timestamps as readable date and time.

• -w

  Waits and shows new messages as they arrive.

• -l niveles

  Shows only those levels, such as err or err,warn.

• -H

  Human-friendly format, with colors and paging.

• -c

  Shows the messages and then clears the buffer (requires root).

• -x

  Shows each message's origin and level in readable form.

• -k

  Shows only kernel messages.

Usage examples

• sudo dmesg | tail

  Shows the latest kernel messages.

• sudo dmesg -T | grep -i usb

  Looks for USB events with the real time.

• sudo dmesg -l err,warn

  Shows only errors and warnings.

• sudo dmesg -w

  Follows messages live while you plug in a device.

Notes and common mistakes

• Some distributions restrict dmesg to root through kernel.dmesg_restrict.
• The buffer has a limited size: old messages are lost.

Related commands

• apt-cache
• cal
• date
• df
• dpkg-deb
• dpkg-query