All the array elements are in a single array:).

Here's your original code. I cleaned it up a little, but davido showed you the best way to do it. Run this, and you'll see why.

#!/usr/bin/perl

use strict;

my @all_metrics = <DATA>;

foreach my $each_metrics_grp (@all_metrics) {
    $each_metrics_grp =~ s/RTRV(.*)//gi;
    my (@sub_metrics) = split( /'\n'/, $each_metrics_grp, 0 );
    my ($matched_true) = grep( /"(([A-Z0-9]+)\-(\d+)),/sig, @sub_metri
+cs );
    print "$1\n";
    print "@sub_metrics";
    if ( $each_metrics_grp =~ m/\"(([A-Z0-9]+)\-(\d+)),/gis ) {
        push my @all_head, $1;
        print "matched:[$1]\n";
    }
    else {
        print "not matched\n";
    }
}

__DATA__
'RTRV-PM-ALL:ADEL-OM3500-1:ALL:1898::,0-UP,NEND,,1-DAY,02-11,,;| ADEL-
+OM3500-1 09-02-12 
03:46:54 M 1898 COMPLD "OC192-11,OC192:CVS,0,COMPL,NEND,RCV,1-DAY,02-1
+1,00-00,1" 

"OC192-11,OC192:ESS,0,COMPL,NEND,RCV,1-DAY,02-11,00-00,1" 
"OC192-11,OC192:PSCW,0,COMPL,NEND,RCV,1-DAY,02-11,00-00,1" 
"OC192-11,OC192:PSCP,0,COMPL,NEND,RCV,1-DAY,02-11,00-00,1" 
"OC192-11,OC192:PSD,0,COMPL,NEND,RCV,1-DAY,02-11,00-00,1" 
"OC192-12,OC192:CVS,0,COMPL,NEND,RCV,1-DAY,02-11,00-00,1" 
"OC192-12,OC192:PSCW,0,COMPL,NEND,RCV,1-DAY,02-11,00-00,1" >';

'RTRV-PM-ALL:ADEL-OM3500-1:ALL:1898::,0-UP,NEND,,1-DAY,02-11,,;| ADEL-
+OM3500-1 
09-02-12 03:46:56 M 1898 COMPLD "OC192-12,OC192:PSCP,0,COMPL,NEND,RCV,
+1-
DAY,02-11,00-00,1" "OC192-12,OC192:PSD,0,COMPL,NEND,RCV,1-DAY,02-11,00
+-00,1" 

"OC192-11-28,STS3C:CVP,0,COMPL,NEND,RCV,1-DAY,02-11,00-00,1" 
"OC192-11-28,STS3C:UASP,0,COMPL,NEND,RCV,1-DAY,02-11,00-00,1" 
"OC192-11-28,STS3C:FCP,0,COMPL,NEND,RCV,1-DAY,02-11,00-00,1" 
"OC192-11-145,STS3C:CVP,0,COMPL,NEND,RCV,1-DAY,02-11,00-00,1" 
"OC192-11-145,STS3C:ESP,0,COMPL,NEND,RCV,1-DAY,02-11,00-00,1" 
"OC192-11-145,STS3C:SESP,0,COMPL,NEND,RCV,1-DAY,02-11,00-00,1" ;';
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