[SOLVED] Any grep, sed or awk gurus with regex familiarity? I need some help.

bcrawl · 01-19-2011, 09:23 AM

hey guys. every one of the above commands worked. Thanks a lot. I have instantly got the awk example from druuna/schenidz but working on sed ones from other guys. But they all work magically. My terminal shows 5 different commands which operate on the same file and give the same output. pretty awesome.

bcrawl · 01-19-2011, 09:38 AM

Quote:

Originally Posted by grail

Based on sycamorex's sed:

Code:

sed -rn 's@</?mfr_id>@@gp' file

could someone please explain the command. How is it extracting it? Is it stripping <mfr_id> and </mfr_id> and leaving the digits or is it extracting the digits...and how does it differ from this one. This will help me understand the process a little bit.

Code:

sed -nr '/mfr_id/ s:[^[:digit:]]*([[:digit:]]+).*:\1:p'

Thanks.

EricTRA · 01-19-2011, 09:47 AM

Quote:

Originally Posted by bcrawl

hey guys. every one of the above commands worked. Thanks a lot. I have instantly got the awk example from druuna/schenidz but working on sed ones from other guys. But they all work magically. My terminal shows 5 different commands which operate on the same file and give the same output. pretty awesome.

Hi,

As usual in Linux, there's always more then one way to skin a cat

I have learned lots from this thread thanks to the gurus here at LQ. Thanks guys.

Kind regards,

Eric

syg00 · 01-19-2011, 04:14 PM

The first sed example strips out (specifically) what is known to be not wanted - it substitutes "null" for it.
The latter case ensures only non-digits start the record, and looks for a string of digits - followed by anything (which could include digits). The bit in parentheses - the string of digits in this case - is retained by the back-reference "\1".

Obvious ain't it ....

. You have to be real careful constructing regex so you don't get unintended results. We've all been there.

schneidz · 01-19-2011, 07:52 PM

@ sycamorex , druuna

Code:

grep mfr_id <input-file> | awk -F "[><]" '{print $3}'

it was really not meant as a full solution but rather a code snippet to point the original poster in the right direction...

and the nit-picky award goes to...