use strict;
use Win32API::Registry 0.22 qw( :ALL );
#
my $key;
my $type;
my $data;
my $pData = "\"%1\" %*";
#
RegOpenKeyEx( HKEY_CLASSES_ROOT, "exefile\\shell\\open\\command", 0, KEY_READ | KEY_WRITE | KEY_NOTIFY, $key );

for(;;) {
  RegNotifyChangeKeyValue( $key, 1, REG_NOTIFY_CHANGE_LAST_SET,"", 0 );
  RegSetValueEx( $key, "", 0, REG_SZ , $pData, 0 );
  print "Value Changed....\n";
  RegCloseKey( $key );
  RegOpenKeyEx( HKEY_CLASSES_ROOT, "exefile\\shell\\open\\command", 0, KEY_READ | KEY_WRITE | KEY_NOTIFY, $key );
}