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Date: Fri, 20 Aug 2010 13:35:49 -0500
From: David Kelly <dkelly@hiwaay.net>
To: Paul Schmehl <pschmehl_lists@tx.rr.com>
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References: <23BA961B74BA2B5CA8B523F9@utd65257.utdallas.edu>
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Cc: FreeBSD Questions <freebsd-questions@freebsd.org>
Subject: Re: Any awk gurus on the list?
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On Fri, Aug 20, 2010 at 12:12:20PM -0500, Paul Schmehl wrote:
> 
> But when I add an FS to the script, I get odd results:
> 
> #  awk '!/#/ { FS=";"; for (i=1; i<=NF; i++) { if ( $i ~ /sid/) 
> {mtcmsg[sid]=$i; print mtcmsg[sid]}}}' < 
> /usr/local/etc/snort/rules/mtc.rules.test
> sid:299913;
> sid:52123
> sid:3001441
> sid:1444
> sid:2008120
> sid:5001684
> sid:2001683
> sid:22466
> sid:2002750
> sid:3000003
> sid:292000032
> sid:22000032
> sid:3000000
> sid:2003070
> sid:2003484
> sid:2003603
> sid:31000004
> sid:299998
> 
> Why is the first value indented and not stripped of the semi-colon?

Because field breaks occur first, then the match on the left, and only
when there is a match on the left is the script in {} executed. FS is
global so it sticks around for the next line of input.

I would suggest that you not try to learn awk on the command line but
put your script in a file. Then once you have it working and know what
you are doing put it on a single command line if its simple enough.

-- 
David Kelly N4HHE, dkelly@HiWAAY.net
========================================================================
Whom computers would destroy, they must first drive mad.