#!/usr/local/bin/perl

use strict;
use warnings;

use Data::Dumper;

my %Diag;
my $file = "2009.txt";
open my $fh, "<", $file or die "Can't open $file: $!";
while (<$fh>)  {
	chomp;
	undef $Diag{$_};
	}

print Dumper \%Diag;

foreach my $k (keys %Diag) {
	print "$k\n";
}