#!/usr/bin/env perl

use strict;
use warnings;
open FILE1, "< file1" or die;
my $keyRef;
while (<FILE1>) {
   chomp;
   $keyRef->{$_} = 1;
}
close FILE1;

open FILE3, "< file3" or die;
while (<FILE2>) {
    chomp;
    my ($testKey, $name) = split("\t", $_);
    if (defined $keyRef->{$testKey}) {
        print STDOUT "$_\n";
    }
}
close FILE3;