protected static function hasNiceSupport()
    {
        exec("nice 2>&1", $niceOutput);

        if (is_array($niceOutput) && isset($niceOutput[0])) {
            if (preg_match('/usage/', $niceOutput[0]) || (preg_match('/^\d+$/', $niceOutput[0]))) {
                /*
                 * Nice is available - default niceness (+10)
                 * https://www.lifewire.com/uses-of-commands-nice-renice-2201087
                 * https://www.computerhope.com/unix/unice.htm
                 */

                return true;
            }
            return false;
        }
    }