protected function _buildCommand()
    {
        $command = $this->_binary;
        $options = (array)$this->getConfig('options');
        foreach ($options as $key => $value) {
            if (empty($value)) {
                continue;
            } elseif ($value === true) {
                $command .= ' --' . $key;
            } else {
                $command .= sprintf(' --%s %s', $key, escapeshellarg($value));
            }
        }

        return $command;
    }