pigeon.php

<?php

$target = "";
$timestamp = date('Y-m-d hms');
$next_cursor = -1;

$f = fopen($target . " - " . $timestamp . ".txt", "w");
while($next_cursor != 0) {
    $api = "https://api.twitter.com/1/followers/ids.xml?cursor=" . 
           $next_cursor . "&screen_name=" . $target;
    $res = simplexml_load_file($api);
    foreach ($res->ids->id as $v) {
        fwrite($f, $v . "\n");
    }
    $next_cursor = $res->next_cursor;
}
fclose($f);