public function executeSimple($commandline, $dir = null, array $env = [])
    {
        $this->stdErr->writeln(
            'Running command: <info>' . $commandline . '</info>',
            OutputInterface::VERBOSITY_VERBOSE
        );

        if (!empty($env)) {
            $this->showEnvMessage($env);
            $env = $env + $this->getParentEnv();
        } else {
            $env = null;
        }

        $this->showWorkingDirMessage($dir);

        $process = proc_open($commandline, [STDIN, STDOUT, STDERR], $pipes, $dir, $env);

        return proc_close($process);
    }