You are getting the uninitialized value warning because $result_1 is undef when fed into print. The real issue is that you are never executing the line $result_1 .= $_;. There are two possibilities I can think of for why this might happen: $res->result() might not return a string as I've assumed or $res->result() is stateful and does not return the same thing on subsequent invocations. I do not have access to documentation on Opsware::NAS::Client, so I can only guess. Two tests you may consider would be running the output through a simple print to make sure you are getting what you expect (print for split /(?<=\n)/, $res->result();) and storing the value in a scalar and feeding that into Data::Dumper (print Dumper $_ = $res->result()).

I copied your Data::Dumper output and filtering loop in to the following code: 

#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;

my $VAR1 = [
          'snmp-server host 10.234.171.38 abcd
snmp-server host 10.234.171.39 abcd
snmp-server host 10.234.171.40 abcd
!snmp-server host 10.10.10.1 xyz
!'
        ];

my $result_1;
for (split /(?<=\n)/, $VAR1->[0]) {
    next unless /^\Qsnmp-server host\E/;
    $result_1 .= $_;
}
print "---Result 1---\n$result_1\n\n";

[download]

which gives me the result 

---Result 1---
snmp-server host 10.234.171.38 abcd
snmp-server host 10.234.171.39 abcd
snmp-server host 10.234.171.40 abcd

[download]

Does this match your expectation?

In reply to Re^5: pulling more data from an array by kennethk
in thread pulling more data from an array by zonevbkr

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