protected function run($cmd)
    {
        $path = getenv('PATH');

        if ($this->prependPath) {
            $path = $this->prependPath . PATH_SEPARATOR . $path;
        }

        $process = new Process($cmd, $this->currentDir(), array(
            'PATH' => $path,
        ));

        $process->run();

        $this->process = $process;

        return $process;
    }