retrieve MAC address

<?php
function getMac(){
exec("ipconfig /all", $output);
foreach($output as $line){
        if (preg_match("/(.*)Physical(.*)/", $line)){
                $mac = $line;
                $mac = str_replace("Physical address. . . . . . . . . :","",$mac);
                $mac = trim($mac);
                echo $mac . "</br>";
        }
}
return $mac;
}

$mac = getMac();
$mac = trim($mac);
echo $mac;
?>




<?php ob_start(); // Turn on output buffering
system("ipconfig /all"); //Execute external program to display output
$mycom=ob_get_contents(); // Capture the output into a variable
ob_clean(); // Clean (erase) the output buffer

$findme = "Physical";
$pmac = strpos($mycom, $findme); // Find the position of Physical text
$mac=substr($mycom,($pmac+36),17); // Get Physical Address

echo $mac;
?>