This works, for example:

#!/usr/bin/perl
use warnings;
use strict;

my $fqdn = 'first';
my $address = 'second';

my @lines = ('RECORDNAME', 'RECORDIP', 'third');

print STDERR "BEFORE: @lines\n";

foreach(@lines) 
    {
       $_ =~ s/RECORDNAME/$fqdn/;
       $_ =~ s/RECORDIP/$address/;
    }

print STDERR "AFTER: @lines\n";
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