private function getCLIConfigs()
    {
        $command = '';
        $combinedConfigs = array_merge($this->globalConfigs, $this->configs);
        if (count($combinedConfigs)) {
            foreach ($combinedConfigs as $config => $value) {
                $command .= sprintf(
                    ' %s %s=%s',
                    escapeshellarg('-c'),
                    escapeshellarg($config),
                    escapeshellarg($value)
                );
            }
        }
        return $command;
    }