use strict;
use warnings;
use Win32::TieRegistry 0.20 (Delimiter=>"/");

sub get_file_association ($) {
   my $x= shift;
   my $reg= $Registry->{"HKEY_CLASSES_ROOT/$x//"}  or return;
   # this usually refers to another entry.
   $reg &&= $Registry->{"HKEY_CLASSES_ROOT/$reg//"} if $x =~ /^\./;
   return $reg;
   }

    
# print get_file_association ('.chm');  example usage (include the dot)
foreach (@ARGV) {
   print $_, '=>', (get_file_association($_) || "NOT KNOWN"), "\n";
   }