Crear un comando CLI personalizado en Magento 2

<?php
namespace GDW\Hello\Console\Command;

use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;

class HelloCommand extends Command
{
    protected function configure()
    {
        $this->setName('gdw:hello')
            ->setDescription('Comando de prueba GDW');
    }

    protected function execute(InputInterface $input, OutputInterface $output)
    {
        $output->writeln('<info>Hola desde un comando custom</info>');
        return 0;
    }
}

<type name="Magento\Framework\Console\CommandList">
    <arguments>
        <argument name="commands" xsi:type="array">
            <item name="gdw_hello" xsi:type="object">GDW\Hello\Console\Command\HelloCommand</item>
        </argument>
    </arguments>
</type>