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

my (%Chr, %R);
my (@key_split, @reg_split);
my ($reg_line);

open(KEY, "<hashKey.txt") or die "error reading key list";
open(REG, "<testReg.txt") or die "error reading file";

while (<KEY>) {

	chomp;
	@key_split = split("\n");
	$Chr{"$key_split[0]"} = $key_split[0];
}

while (<REG>) {

	chomp;
	@reg_split = split("\t");
	#$R{"$reg_split[0]"} = ($reg_split[0], $reg_split[1], $reg_split[2], $reg_split[3]);
	$R{"$reg_split[0]"} = $reg_split[0];
}


foreach my $key (keys %Chr) {
	if(exists($R{$key})){
		print ("$R{$key}\n");
	}
}
close(KEY);
close(REG);