Date: Fri, 22 Aug 2008 17:18:01 -0700 From: Walt Pawley <walt@wump.org> To: freebsd-questions@FreeBSD.ORG, Oliver Fromme <olli@lurza.secnetix.de> Subject: Re: sed/awk, instead of Perl Message-ID: <p0624080cc4d504c10465@[10.0.0.10]> In-Reply-To: <200808220759.m7M7xuh0047625@lurza.secnetix.de> References: <200808220759.m7M7xuh0047625@lurza.secnetix.de>
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At 9:59 AM +0200 8/22/08, Oliver Fromme wrote:
> - The perl command you wrote above is pretty much a sed
> command anyway (except you incorrectly used non-portable
> regular expression syntax). Why use perl to execute a
> sed command?
At the risk of beating this to death, I just happened to
stumble on a real world example of why one might want to use
Perl for sed-ly stuff. I wanted to pull off the accessor's
address from each line of an Apache access log file. So, I
figured after this discussion that sed was the way to go. Then
I got curious and did the following:
wump$ ls -l Desktop/klog
-rw-r--r-- 1 wump 1001 52753322 22 Aug 16:37 Desktop/klog
wump$ time sed "s/ .*//" Desktop/klog > kadr1
real 0m10.800s
user 0m10.580s
sys 0m0.250s
wump$ time perl -pe 's/ .*//' Desktop/klog > kadr2
real 0m0.975s
user 0m0.700s
sys 0m0.270s
wump$ cmp kadr1 kadr2
wump$
Why disparity in execution speed? Beats me, but my G5's fans
started to take off running the sed command. I don't think the
Perl command took long enough to register thermally. Curious.
FWIW: I did this with an older version of Mac OS X, rather
FreeBSD so it could easily not show the same results if I moved
the log file to a FreeBSD box and did it there.
--
Walter M. Pawley <walt@wump.org>
Wump Research & Company
676 River Bend Road, Roseburg, OR 97470
541-672-8975
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