automatic file deletion

need a helping hand here...in this php file the script will automatically delete all files older than the time I set....the only thing is that I would want it to delete everything except an .htaccess file I have in there...
another thing i would want it to do is go into three seperate folders to delete the items...not subdirectories within that first one...

<?php
function delete_old_files($dir, $time_limit = 0){
 if(!$time_limit) $time_limit = 1*24*60*60;
 if ($df = opendir($dir)) {
  while (false !== ($file = readdir($df))) {
   if ($file != "." && $file != "..") {
    $last_modified = filemtime($file);
    if(time()-$last_modified > $time_limit){
     unlink($file);
    }
   }
  }
  closedir($df);
 }
}

delete_old_files('.');

?>

PHP:

 

umm i think the htaccess part if pretty simple , you can create a third parameter for that function. and to delete from three seperate folders, call the function 3 times i reckon!

something like this

function delete_old_files($dir, $time_limit = 0,$exclude=array()){
 if(!$time_limit) $time_limit = 1*24*60*60;
 if ($df = opendir($dir)) {
  while (false !== ($file = readdir($df))) {
   if ($file != "." && $file != "..") {
    $last_modified = filemtime($file);
	
    if((time()-$last_modified > $time_limit) && !in_array($file , $exclude)){
     unlink($dir."/".$file);
    }
   }
  }
  closedir($df);
 }
}

delete_old_files('folder1' , 10 , array('.htaccess'));
delete_old_files('folder2' );
delete_old_files('folder3' );

PHP:

 

am i missing something? it seems as if though everytime I run it all files get deleted including recent ones...