Wriitng to a certain line on a file

[mrxxlphp]

Hi guys, I am making a control panel with varying levels of access. When add a user it makes a file like this:

<?php

$userban="0";
$pass="**********";
$username="stuart";
$userrealname="Stuart Baggs";
$useremail="[e-mail]";

?>

Now if I want to suspend someone’s account, how can I change just the line that says $userban="0"; to $userban="1"; without changing the whole file.

Thanks in advance. Stuart

[laserlight]

perhaps use regexp to search and replace the
$userban="int n";
line?