-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Mark Goldstein wrote:

Hi,

On Jan 7, 2008 2:37 PM, G T Smith wrote:

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Marcin Floryan wrote:

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Hi!

Anyone have any view over the best way to watch for changes in log files to do some analysis? ... * to use Perl File::Tail to listen on a file and process any text that arrives * to use tail -f and pipe the output to my software ...

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Personal view is that it would be best to use a Perl module if it exists in a script daemon, rather than use a command line call and pipe data to a perl script.

Not on performance grounds, but more because one can design the script to handle unusual events and manage processing accordingly (especially if you are backending with a database that in itself may be adding to the logs you are monitoring).

I guess, it depends on what one wants to do with the logs. I used "tail" in a set of tests and found it very flexible and convenient. E.g. I did not want to know exactly in what log file the

<snip> It always does :-) If one is only filtering this is probably fine, as is the approach of using syslog suggested elsewhere ... but the thing I am picking up here is the perl script is intended to talk to something else as well (a database backend by the look of it). The Perl tail related modules offer a variety of options for performing this, Also without the need to call tail or any piping (e.g. File::Tail::App, Event::File::Tail, IO::Tail and File::Tail::FAM all seem to be possibilities here)....

Regards,

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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The Monday 2008-01-07 at 16:12 +0200, Mark Goldstein wrote:

Sure, I just gave one example where I thought "tail" was good enough and provided quick solution (not "quick and dirty"). I have to admit, I did not use "File::Tail" from pure ignorance and laziness :-). I'll definitely look into it next time I'll need to to something of this sort.

If you go the "tail -f" way, then you'd better use "tailf" instead. Its a different program that doesn't cause unnecesary disk activity. DESCRIPTION tailf will print out the last 10 lines of a file and then wait for the file to grow. It is similar to tail -f but does not access the file when it is not growing. This has the side effect of not updating the access time for the file, so a filesystem flush does not occur periodically when no log activity is happening. tailf is extremely useful for monitoring log files on a laptop when logging is infrequent and the user desires that the hard disk spin down to conserve battery life. - -- Cheers, Carlos E. R. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4-svn0 (GNU/Linux) iD8DBQFHgkZjtTMYHG2NR9URAsrvAJ0Sv2cUijoQVbb7p4mbij4W9MNL7ACgik+A s5uV9JrETNOBODlMGG2nTS4= =UJsx -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org