#!/usr/bin/perl -W
use strict;
use warnings;
my %hash;
$hash{test}{1} = 'test1';
$hash{test}{1}{test2} = 'test3';
$hash{test}{2} = 'test5';
foreach my $nr (
	grep {exists $hash{test}{$_}{test2}}
	keys %{$hash{test}}
) {
	print $nr;
}