OS Information Get Using PhP

function getOSInformation()
{
    if (false == function_exists("shell_exec") || false == is_readable("/etc/os-release")) {
        return null;
    }

    $os         = shell_exec('cat /etc/os-release');
    $listIds    = preg_match_all('/.*=/', $os, $matchListIds);
    $listIds    = $matchListIds[0];

    $listVal    = preg_match_all('/=.*/', $os, $matchListVal);
    $listVal    = $matchListVal[0];

    array_walk($listIds, function(&$v, $k){
        $v = strtolower(str_replace('=', '', $v));
    });

    array_walk($listVal, function(&$v, $k){
        $v = preg_replace('/=|"/', '', $v);
    });

    return array_combine($listIds, $listVal);
}