#use strict;
open ALUS, "Z:\\3\' UTR intron project\\Alu_bed.bed" ||die "couldn't open alus!!";

my %seen;
while (<ALUS>){
	/(chr.*?)\t/;
	if (exists $seen{$1}){
		print $1 "$_";
	}else{
	$seen{$1}="whatever";
		open $1, ">Z:\\3\' UTR intron project\\Alu_chroms\\$1.txt"||die "couldn't open $1 file!";
               print $1 "$_";
	}
}