online user kodu istek

<?

$rip = $_SERVER['REMOTE_ADDR'];
$sd  = time();
$onlineUsers = 1;
$file1 = "ip.txt";
$lines = file($file1);
$line2 = "";
foreach ($lines as $line_num => $line)
{
$fp = strpos($line,'****');

 $nam = substr($line,0,$fp);
$sp = strpos($line,'++++');
$val = substr($line,$fp+4,$sp-($fp+4));
$diff = $sd-$val;
if($diff < 300 && $nam != $rip)
{
$onlineUsers = $onlineUsers+1;
$line2 = $line2.$line;
}
}
$my = $rip."****".$sd."++++\n";
$open1 = fopen($file1, "w");
fwrite($open1,"$line2");
fwrite($open1,"$my");
fclose($open1);
echo "$onlineUsers";
?>