Building a single Command Application

When building a command line tool, you may not need to provide several commands. In such case, having to pass the command name each time is tedious.

New in version 5.1: The SingleCommandApplication class was introduced in Symfony 5.1.

Fortunately, it is possible to remove this need by declaring a single command application:

#!/usr/bin/env php
<?php
require __DIR__.'/vendor/autoload.php';

use Symfony\Component\Console\Input\InputArgument;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Input\InputOption;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\Console\SingleCommandApplication;

(new SingleCommandApplication())
    ->setName('My Super Command') // Optional
    ->setVersion('1.0.0') // Optional
    ->addArgument('foo', InputArgument::OPTIONAL, 'The directory')
    ->addOption('bar', null, InputOption::VALUE_REQUIRED)
    ->setCode(function (InputInterface $input, OutputInterface $output) {
        // output arguments and options
    })
    ->run();

You can still register a command as usual:

#!/usr/bin/env php
<?php
require __DIR__.'/vendor/autoload.php';

use Acme\Command\DefaultCommand;
use Symfony\Component\Console\Application;

$application = new Application('echo', '1.0.0');
$command = new DefaultCommand();

$application->add($command);

$application->setDefaultCommand($command->getName(), true);
$application->run();

The setDefaultCommand() method accepts a boolean as second parameter. If true, the command echo will then always be used, without having to pass its name.