LinuxLogFile format in Ubuntu 8.04

Alvaro del Olmo seiken at
Fri Jun 20 07:51:55 UTC 2008

Numbers in square brackets are a timestamp attached to the message, which
can be useful to debug problems. Its format is [seconds.microseconds], and
it begins from boot up (see (var/log/dmesg; it begins from 0.0). This
timestamp is ussually appended in when 'printk( )' function is called by the
kernel itself.
To disable it you may alter CONFIG_PRINTK_TIME kernel variable, but i'm sure
someone has another best suggest.


Álvaro del Olmo.

2008/6/19, Douglas Gilbert <dgilbert at>:
> I can find no explanation of the proforma part of log file
> entries.
> Here is a typical entry from /var/log/messages:
> Jun 19 10:17:23 rink kernel: [   25.352589] agpgart: Putting AGP V2 ...
> Where is that format defined (from the start of line to
> 'agpgart:' in this case)? Why was the square bracket enclosed
> section added? What is it? [Seconds since boot up?]. What tools
> can decode what is in the square brackets? Can the proforma part
> of a log entry be user configured?.
> The LinuxLogFile document could be enhanced by adding a section
> to explain the log file output format.
> Doug Gilbert
> --
> ubuntu-doc mailing list
> ubuntu-doc at
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