DMESG(8) | System Manager's Manual | DMESG(8) |
dmesg
—
dmesg |
[-dTt ] [-M
core] [-N
system] |
dmesg
displays the contents of the system message
buffer.
The options are as follows:
-d
-t
only the deltas are shown.-M
-N
-T
-t
The system message buffer is a circular buffer of a fixed size. If
the buffer has been filled, the first line of the
dmesg
output may not be complete. The size of the
message buffer is configurable at compile-time on most systems with the
MSGBUFSIZE
kernel option. Look for
MSGBUFSIZE
in
options(4) for details.
dmesg
command appeared in
3.0BSD.
-T
option will report nonsense when displaying lines
from the message buffer that were not added by the current running kernel.
When -TT
is used, the duration is always
given with maximum units of hours, even when the number of hours is in the
hundreds, thousands, or more. This is because converting hours to days, over
periods when “time skips” occur, such as summer time beginning
or ending, is not trivial. A duration of 26 hours might be 1D3H or 1D1H at
such events, rather than the usual 1D2H, and when a time zone alters its
offset, even more complex calculations are needed. None of those
calculations are done (even to account for sub-hour time zone shifts), the
duration indicated is always calculated by simple division of seconds by 60
to produce minutes, and again to produce hours. Most of the time [!]
this is correct.
October 30, 2018 | NetBSD 9.4 |