PHP/File Directory/realpath

Cleaning up a file name with realpath()

   <source lang="html4strict">

$filename = realpath("/usr/local/data/$_POST[user]"); if ("/usr/local/data/" == substr($filename, 0, 16)) {

   print "User profile for " . htmlentities($_POST["user"]) .": 
";
   print file_get_contents($filename);

} else {

   print "Invalid user entered.";

}

 </source>
   
  

realpath.php

   <source lang="html4strict">

<?php

    $imgPath = "../cover.gif";
    $absolutePath = realpath($imgPath); 
    echo $absolutePath;

?>

 </source>