$con = "<?php\r\nreturn " . var_export($config, true) . ";\r\n?>";
$aa = file_put_contents($path, $con);

$str = file_get_contents("config.php");
$str = preg_replace("/Access_Token = (.*);/","Access_Token = \"".$new_token."\";",$str);
$aa = file_put_contents("config.txt", $str);