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Full Discussion: grep sed and a loop
Top Forums UNIX for Dummies Questions & Answers grep sed and a loop Post 302521308 by agama on Tuesday 10th of May 2011 10:32:32 PM
Old 05-10-2011
It sounds like you're working with a daemon's log file and if so you'll need to be careful. If you overlay the open log file, you'll stop seeing updates to the file as you will have unlinked the open file from the directory and replaced it with a static file that you marked up with hash (#) signs.

I think you have two choices:

1) use tail -f to read the log file and pipe the output through grep or awk to do what you need. This is probably easiest.

2) if your log file has timestamps then you can run your search periodically. With each run save the last time stamp in the log file, tuck it away in a /tmp file or something, and only process messages in the log that have a timestamp greater than the last one saved.

Small sample of using tail:
Code:
tail -f /var/log/foo | grep "Can not load CRL"  >capture-file

 

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LEARN ABOUT SUSE

scanlogs

SCANLOGS(8)						    InterNetNews Documentation						       SCANLOGS(8)

NAME

       scanlogs - Summarize and rotate INN log files

SYNOPSIS

       scanlogs [norotate]

DESCRIPTION

       scanlogs summarizes the information recorded in the INN log files which reside in the pathlog directory set in inn.conf (see newslog(5) for
       further details about these log files).	It is normally invoked by the news.daily(8) script which performs daily server maintenance tasks.

       It invokes "ctlinnd flushlogs" to close the news and error log files, rename them to add ".old" to the file names and open fresh news and
       error logs; the active file is also flushed to disk, along with the history database.

       By default, scanlogs rotates and cleans out the logs.  It keeps up to logcycles old compressed log files in pathlog/OLD (the logcycles
       parameter can be set in inn.conf).   scanlogs also keeps archives of the active file in this directory.

       It invokes tally.control if newgroup.log or rmgroup.log exists in pathlog (see the control.log entry of newslog(5) for more information
       about that).

       scanlogs displays the contents of errlog and news.crit, if non-empty, and runs innreport to summarize the contents of news and news.notice,
       and to update the unwanted.log file amongst other things (see more information about that in innreport(8)).

OPTIONS

       Only one option is currently accepted:

       norotate
	   Using this option disables the rotating and cleaning aspect of the log processing:  the logs files are only scanned for information and
	   no contents are altered.  If scanlogs is invoked more than once a day, the norotate option should be used to prevent premature log
	   cleaning.

FILES

       See newslog(5) for the list of log files processed by scanlogs.

HISTORY

       Written by Landon Curt Noll <chongo@toad.com> and Rich $alz <rsalz@uunet.uu.net> for InterNetNews.  Converted to POD by Julien Elie.

       $Id: scanlogs.pod 8357 2009-02-27 17:56:00Z iulius $

SEE ALSO

       inn.conf(5), innreport(8), news.daily(8), newslog(5), shlock(1), tally.control(8).

INN 2.5.2							    2009-05-21							       SCANLOGS(8)
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