use Symfony\Component\Console\Application; use Symfony\Component\Console\Command\Command; use Symfony\Component\Console\Input\InputInterface; use Symfony\Component\Console\Output\OutputInterface; class MyCommand extends Command { protected function configure() { $this->setName('mycommand') ->setDescription('A brief description of my command'); } protected function execute(InputInterface $input, OutputInterface $output) { $output->writeln('Hello, world!'); } } $app = new Application(); $app->add(new MyCommand()); // Show help for the entire application echo $app->getHelp(); // Show help for a specific command echo $app->get('mycommand')->getHelp();In this example, we define a simple command called "mycommand" that outputs "Hello, world!" when executed. We then create a new instance of the Application class and add our command to it. Finally, we call getHelp() to display usage information for the application or for the "mycommand" command. This component is part of the Symfony Console package library, which provides functionalities for creating command-line applications.