use Win32 ;

my $REGISTER;
use Win32::TieRegistry (Delimiter=>"/", ArrayValues=>1, TiedRef=>\$REG
+ISTER) ;

sub get_filetype_cmd {
  my ( $type ) = @_ ;

  my $app = $REGISTER->{"HKEY_CLASSES_ROOT/.$type//" };
  my $cmd = $REGISTER->{"HKEY_CLASSES_ROOT/$$app[0]/shell/open/command
+//" };

  $cmd = $$cmd[0] ;
  $cmd =~ s/"(.*?)".*/$1/s ;
  $cmd =~ s/(\.exe|\.bat|\.com).*/$1/si ;

  return( $cmd ) ;
}

1;
[download]

Usage:

  my $exec = get_filetype_cmd('xls');
  open (CMD,"| $exec file.xls") ; close (CMD) ;
[download]

Note that if you make just

open (CMD,"| file.xls") ;
[download]

on Win32 it will open Excel, but with an adicional console window if you don't have a console APP. But if you want, for example, create a new process (that doesn't open a console), you really need the executable.