how to make this php script loop and write to a text file?

[Brad]

I want it to make 100 passwords and then write the results to a text file.. can someone edit it for me

<?php

$password_length = 7;

function make_seed() {
list($usec, $sec) = explode(' ', microtime());
return (float) $sec + ((float) $usec * 100000);
}

srand(make_seed());

$alfa = "1234567890!@#$%^&*qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM";
$token = "";
for($i = 0; $i < $password_length; $i ++) {
$token .= $alfa[rand(0, strlen($alfa))];
}
echo $token;
sleep(238497239);


?>
I made that into a php file and it closes instantly