#!/usr/bin/perl
use strict;
use warnings;
use 5.016;

my @lines = ("RECORDNAME foo bar baz RECORDIP 127.2.2.1 \n", "RECORDNAME 1 2 3 4 5 RECORDIP 127.1.1.1\n", "RECORDNAME abcd e fgh ij RECORDIP 127.0.0.1\n");
my $fqdn = qq/www.test.sample/;
my $address = qq/nowhere_ville/;

say @lines;
say "-" x10 . "\n";

my @newlines = '';

for $_(@lines) {
   $_ =~ s/RECORDNAME/$fqdn/;     #no need to /ee if your vars are scalars
   $_ =~ s/RECORDIP/$address/;
   push(@newlines, $_);
}

say @newlines;