$pre= "\\*\\*";                                             
$post = "%%"; 
$firstchar = substr($post,0,1); 
$text = "**this is good%% blah **this is bad%%%%%% blah ***this is bad%%%blah"; 
                                                        
@parts = split(/($pre.*?$firstchar*$post)/,$text); 
 
foreach $part (@parts) { 
  print "part: $part\n"; 
}