dmesg(8)

dmesg8

Display the system message buffer

Usage

dmesg [-s] [-M core] [-N system]

Overview

dmesg displays the contents of the system message buffer. It is most commonly used to review system startup messages. On some systems the message buffer can survive reboot and be retained (in the hope of exposing information from a crash).

The options are as follows:

-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 /bsd.

-s

Display the contents of the console message buffer instead. This can be used to review rc(8) system startup messages. This option is limited to the superuser.

Files

/var/run/dmesg.boot

copy of dmesg saved by rc(8) at boot time

Releases

61 releases since OpenBSD 2.1; the text changed 12 times.

  1. 2.1–2.3
  2. 2.4
  3. 2.5
  4. 2.6
  5. 2.7–3.3
  6. 3.4–4.1
  7. 4.2–4.9
  8. 5.0–5.4
  9. 5.5–5.6
  10. 5.7
  11. 5.8–6.0
  12. 6.1–7.5
  13. 7.6–8.0

-s since OpenBSD 5.7.

History

The dmesg command appeared in Version 7 AT&T UNIX.

From man 8.0-current-20261101 in OpenBSD 8.0-current (2026-11-01). Parsed by carta from the page's mdoc source.