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I have (for example) this log entry in dmesg output:

[600711.395348] do_trap: 6 callbacks suppressed

Is there a possibility to convert this 'dmesg' time to 'real' time to know, when this event happend?

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3 Answers 3

up vote 21 down vote accepted

It looks as if it was implemented recently for Quantal (12.10) : see http://brainstorm.ubuntu.com/idea/17829/ .

Basically, dmesg is reported to have a new switch -T, --ctime.

Edit. As another extension on Ignacio's answer, here are some scripts to enhance dmesg output on older systems.

( Note: for the python version of the code shown there, one will want to replace &lt; and &gt; back to <> to make it usable again. )

Finally, for a single value like 600711.395348 one could do

ut=`cut -d' ' -f1 </proc/uptime` 
ts=`date +%s` 
date -d"70-1-1 + $ts sec - $ut sec + 600711.395348 sec" +"%F %T"

and get the event date and time.

( Please note that due to round-off errors the last second digit probably won't be accurate. ) .

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To extend on Ignacio's answer, the entries contained in dmesg are typically also logged elsewhere on the system, via syslog, which will give you a "real" timestamp. Unless Ubuntu have changed the Debian-set default, the log entries should be in /var/log/kern.log.

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Thanks for a note... –  Jan Marek Mar 5 '12 at 8:59

The time given in dmesg is in seconds since kernel startup. So, just add that many seconds to when the kernel started running (hint: uptime).

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Thanks a lot... –  Jan Marek Mar 5 '12 at 8:58

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