validateProfile example

    chdir(dirname(__DIR__, 5));

    // Check whether there is already an installation.     if ($this->isDrupalInstalled()) {
      // Do not fail if the site is already installed so this command can be       // chained with ServerCommand.       $output->writeln('<info>Drupal is already installed.</info> If you want to reinstall, remove sites/default/files and sites/default/settings.php.');
      return 0;
    }

    $install_profile = $input->getArgument('install-profile');
    if ($install_profile && !$this->validateProfile($install_profile, $io)) {
      return 1;
    }
    if (!$install_profile) {
      $install_profile = $this->selectProfile($io);
    }

    return $this->install($this->classLoader, $io, $install_profile, $input->getOption('langcode'), $this->getSitePath(), $input->getOption('site-name'));
  }

  /** * Returns whether there is already an existing Drupal installation. * * @return bool */