Revisar Script de usuarios online

[yaviz]

Hola, encontre este script, pero no lo entiendo muy bien, me gustaria me dijerais si esta bien hexo y me explicarais un pokito ke es lo ke hase y si hay ke configurar algo.
Gracias.Un saludo.



USERONLINE.PHP4
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<?php
include ("./config.php3");

if (!$datei) $datei = dirname(__FILE__)."/$filename";
$time = @time();
$ip = $REMOTE_ADDR;
$string = "$ip|$time\n";
$a = fopen("$filename", "a+");
fputs($a, $string);
fclose($a);

$timeout = time()-(60*$timer);

$all = "";
$i = 0;
$datei = file($filename);
for ($num = 0; $num < count($datei); $num++) {
$pieces = explode("|",$datei[$num]);

if ($pieces[1] > $timeout) {
$all .= $pieces[0];
$all .= ",";
}
$i++;
}

$all = substr($all,0,strlen($all)-1);
$arraypieces = explode(",",$all);
$useronline = count(array_flip(array_flip($arraypieces)));

// display how many people where activ within $timeout
echo $useronline;

// Delete
$dell = "";
for ($numm = 0; $numm < count($datei); $numm++) {
$tiles = explode("|",$datei[$numm]);
if ($tiles[1] > $timeout) {
$dell .= "$tiles[0]|$tiles[1]";
}
}

if (!$datei) $datei = dirname(__FILE__)."/$filename";
$time = @time();
$ip = $REMOTE_ADDR;
$string = "$dell";
$a = fopen("$filename", "w+");
fputs($a, $string);
fclose($a);
?>
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CONFIG.PHP3
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<?php

// Timeout - After this time the users will*
// be deleted (in minutes)
$timer = 100;

// Name of the file where all the data, about
// the user's activity will be saved
$filename = "$DOCUMENT_ROOT/useronline/log.txt";

?>
--------------------------------------------------------------------------

LOG.TXT

esta vacio
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