my @hist;
sub print_hash {

    my($href) = @_;

    foreach my $key (keys %$href) {
        if (ref($$href{$key}) eq 'HASH') {
            my $href2 = $$href{$key};
            push @hist, $key;
            print_hash($href2);
            pop @hist;
        } else {
           foreach my $h(@hist) {
               print $h."/";
           }
           print "$key => $$href{$key}\n";
        }
    }
}