I may have misinterpreted the question before. If you want the "output start" and "output end" marker lines in the output (which I guess your grep pipeline would do), then Adam's sed script will do that. Mine, using the "d" commands, will output only the data in between. The shortest awk script to do the same would be:
awk '/output start/{s=1};s==1;/output end/{s=0};'
or
awk '/output end/{s=0};s==1;/output start/{s=1};'
The first is a simplification of Adam's, which outputs the output marker lines, while the second, using the same statements in the opposite order, suppresses the markers. Of perl, awk and sed, I suspect sed is the most lightweight, and probably the quickest, unless perl can outperform sed on larger files. awk has a reputation for being pretty slow. I tend to favour sed unless awk or perl makes the job a lot easier.
Gilles
On 11/10/2010 11:13 AM, Adam Thompson wrote:
The AWK version is functionally identical, and not very much shorter, or any more elegant:
awk ‘/output start/ {s=1};{if (s==1) print $0};/output end/ {s=0}’(the perl version can generally be made that small, too.)
I would instead suggest sed(1), since this is precisely what it’s designed for:
sed –n ‘/output start/,/output end/p’ < infile-Adam
*From:* roundtable-bounces@muug.mb.ca [mailto:roundtable-bounces@muug.mb.ca] *On Behalf Of *Sean Walberg *Sent:* Wednesday, November 10, 2010 10:56 *To:* Continuation of Round Table discussion *Subject:* Re: [RndTbl] Command line challenge: trim garbage from start and end of a file.
OTTOMH:
perl -n -e 'BEGIN {$state = 0} $state = 1 if ($state == 0 and /output start/); $state = 2 if ($state == 1 and /output end/) ; print if ($state == 1)' < infile > outfile
I'll bet there's a shorter AWK version though.
Sean
On Wed, Nov 10, 2010 at 10:51 AM, John Lange <john@johnlange.ca mailto:john@johnlange.ca> wrote:
I have files with the following structure:
garbage garbage garbage output start .. good data .. good data .. good data .. good data output end garbage garbage garbage
How can I extract the good data from the file trimming the garbage from the beginning and end?
The following works just fine but it's dirty because I don't like the fact that I have to pick an arbitrarily large number for the "before" and "after" values.
grep -A 999999 "output start" <infile> | grep -B 999999 "output end" > newfile
Can anyone come up with something more elegant?
-- John Lange www.johnlange.ca http://www.johnlange.ca