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

dmesg — display the system message buffer

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

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:

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

/var/run/dmesg.boot
copy of dmesg saved by rc(8) at boot time

syslogd(8)

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

OpenBSD 7.8 June 30, 2024 DMESG(8)