*blows dust off perlmonks.org account. I've been away a while, but thought my Perl-fu was up to this rather simple task.

I believe I'm suffering from a rather simple misunderstanding of the /x modifier, and of the {} quantifiers. It's also the first time I've used the named capture buffers, but I'm not sure that matters.

Here's a complete script which should produce a match, so what have I done wrong? 

#!/usr/bin/perl

use warnings;
use strict;
use Data::Dumper;


my $vg_details = '
   --- Physical volumes ---
   PV Name                     /dev/dsk/c14t3d1
   PV Name                     /dev/dsk/c15t3d1 Alternate Link
   PV Status                   available                
   Total PE                    15997   
   Free PE                     0       
   Autoswitch                  On        
   Proactive Polling           On               
';

while($vg_details =~ m/^\s*PV\s+Name\s*(?<pv_name>\S+)\s*$
    (^\s*PV\s+Name\s+(?<alt_link>\S+)\s+Alternate\s+Link\s*$){0,20}   
+# skip them
    ^\s*PV\s+Status\s+(?<pv_status>\S+)\s*$
    ^\s*Total\s+PE\s+(?<total_pe>\S+)\s*$
    ^\s*Free\s+PE\s+(?<free_pe>\d+)\s*$
    ^\s*Autoswitch\s+(?<autoswitch>\S+)\s*$
    ^\s*Proactive\s+Polling\s+(?<proactive_polling>\S+)\s*$/gsmx) {
    my $pv_name           = $+{pv_name};
    print "matched $pv_name";
}

[download]

The example data is slightly contrived, in that the "Alternate Link" lines are optional (and there may be many). Removing the additional 6 lines below the "PV Name" line in the regex makes it work, so have I completely confused the multi-line comment switch?

Also, I know this is a slightly ludicrous method to process VG data, but I've been handed a big, big list of "vgdisplay -v" output, and this particular edge case is failing. I've reduced it to this minimal example and my eyes still can't spot what's wrong. What silly mistake am I making?


davis

In reply to Regular expression quantifiers and the /gsmx modifiers by davis

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