Passing Varables to file beign generated in script.

[ringworld]

This is what I have so far.

//make user file
$thetext="
<?php
//Call Database & Connect
require_once('headers/database.php');
connect();
//will this work?
        $user_name
?>";
$user_file_name = $_POST['user_name'];
$filename="profiles/$user_file_name/$user_file_name.php";
$tempvar = fopen($filename,"w");
	fwrite($tempvar, $thetext);
	fclose($tempvar);

What I am trying to do is pass a variable, $user_name, into this file that is being generated. Lets say $user_name is ringworld, I want the written file to contain is "$ringworld" not $user_name. Can this be done? If so how? I am confused so I don't expect you guys to understand what I mean, If you need to know more just ask!

 

Thanks!