PHP Online edit file

 <?php  
   
 // configuration  
 $url = 'http://[domain]/editor.php';  
 $dir = '/[path to file]/';  
 $nama = 'index.php';  
   
 // check nama, call: [$url]?nama=[file to edit]  
 if (isset($_GET['nama']))  
 {  
   $nama=$_GET['nama'];  
 }  
 $file = $dir.$nama;  
   
 // check if form has been submitted  
 if (isset($_POST['text']))  
 {  
   // save the text contents  
   file_put_contents($file, $_POST['text']);  
   
   // redirect to form again  
   header(sprintf('Location: %s', $url.'?'.'nama='.$nama));  
   printf('<a href="%s">Moved</a>.', htmlspecialchars($url));  
   exit();  
 }  
   
 // read the textfile  
 $text = file_get_contents($file);  
   
 ?>  
 <!-- HTML form -->  
 <form action="" method="post">  
 <input name="nama" value="<?php echo $nama; ?>"/>  
 <textarea name="text" style="width: 100%; height:80%;"><?php echo htmlspecialchars($text) ?></textarea>  
 </br>  
 <input type="submit" />  
 <input type="reset" />  
 </form>