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Re: Regular expression in awk

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On 06.04.2011 16:40, gio001 wrote:
> Hello,
> I have thousand of messages (HL7),

Provide sample data for a few HL7 records.

> I want to use awk to extract only
> the ones that have a particular value in pv1.18

Define what you mean by "pv1.18".

> Each record in the file is the whole HL7 message, ie. when I print $0
> I get the whole message MSH EVN PID etc. ,there is an x0d between the

You mean a single ASCII CR character separates some entity in the data?

> segments.

Define what a segment in your sample data is.

> I would like to use a line somewhat like:
> 
> awk '{if(/PV1\|\([^|]*\|\)\{16\}\|X/){print $0}}' infile > outfile

In awk you can write

  /pattern/ { action }

instead of

  { if ($0 ~ /pattern/) action }

> 
> I do not seem to be able to get this working properly in awk on a AIX
> box.
> Yet this statement works fine against the infile:
> 
> grep 'PV1\|\([^|]*\|\)\{16\}\|X' infile

Gee! What's that cryptic expression supposed to do?

Please don't try to give your cryptic tries without explaining what you
actually want to achieve.

> 
> Can anyone please help?

It may help you to know that in awk you can define the field separator
and record separators. Then you can access individual fields in a simple
way. Say, your field separator is | (a pipe symbol) and you want to
extract the 18th field only in lines where you've some pattern /PV1/:

  awk -F\| '/PV1/ { print $18 }' infile


Janis

> Thanks.

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Regular expression in awk gio001 <gcrippa@gmail.com> - 2011-04-06 07:40 -0700
  Re: Regular expression in awk pk <pk@pk.invalid> - 2011-04-06 16:01 +0100
  Re: Regular expression in awk Janis Papanagnou <janis_papanagnou@hotmail.com> - 2011-04-06 19:24 +0200
    Re: Regular expression in awk Manuel Collado <m.collado@domain.invalid> - 2011-04-06 21:07 +0200
    Re: Regular expression in awk gio001 <gcrippa@gmail.com> - 2011-04-06 12:25 -0700
      Re: Regular expression in awk Janis Papanagnou <janis_papanagnou@hotmail.com> - 2011-04-06 23:09 +0200
        Re: Regular expression in awk gio001 <gcrippa@gmail.com> - 2011-04-06 19:59 -0700
          Re: Regular expression in awk Loki Harfagr <l0k1@thedarkdesign.free.fr.INVALID> - 2011-04-07 07:32 +0000
            Re: Regular expression in awk gio001 <gcrippa@gmail.com> - 2011-04-07 05:06 -0700
              Re: Regular expression in awk Loki Harfagr <l0k1@thedarkdesign.free.fr.INVALID> - 2011-04-07 13:34 +0000
                Re: Regular expression in awk gio001 <gcrippa@gmail.com> - 2011-04-07 08:27 -0700
                Re: Regular expression in awk Loki Harfagr <l0k1@thedarkdesign.free.fr.INVALID> - 2011-04-07 18:32 +0000
      Re: Regular expression in awk Geoff Clare <geoff@clare.See-My-Signature.invalid> - 2011-04-07 13:34 +0100
        Re: Regular expression in awk arnold@skeeve.com (Aharon Robbins) - 2011-04-07 13:31 +0000
          Re: Regular expression in awk Geoff Clare <geoff@clare.See-My-Signature.invalid> - 2011-04-08 13:18 +0100

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