Using Command Arguments

Arguments are the strings - separated by spaces - that come after the command name itself. They are ordered, and can be optional or required. For example, to add an optional last_name argument to the command and make the name argument required:

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// ...
use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputArgument;

class GreetCommand extends Command
{
    // ...

    protected function configure(): void
    {
        $this
            // ...
            ->addArgument('name', InputArgument::REQUIRED, 'Who do you want to greet?')
            ->addArgument('last_name', InputArgument::OPTIONAL, 'Your last name?')
        ;
    }
}

You now have access to a last_name argument in your command:

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

class GreetCommand extends Command
{
    // ...

    protected function execute(InputInterface $input, OutputInterface $output): int
    {
        $text = 'Hi '.$input->getArgument('name');

        $lastName = $input->getArgument('last_name');
        if ($lastName) {
            $text .= ' '.$lastName;
        }

        $output->writeln($text.'!');

        return 0;
    }
}

The command can now be used in either of the following ways:

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$ php bin/console app:greet Fabien
Hi Fabien!

$ php bin/console app:greet Fabien Potencier
Hi Fabien Potencier!

It is also possible to let an argument take a list of values (imagine you want to greet all your friends). Only the last argument can be a list:

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$this
    // ...
    ->addArgument(
        'names',
        InputArgument::IS_ARRAY,
        'Who do you want to greet (separate multiple names with a space)?'
    )
;

To use this, specify as many names as you want:

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$ php bin/console app:greet Fabien Ryan Bernhard

You can access the names argument as an array:

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$names = $input->getArgument('names');
if (count($names) > 0) {
    $text .= ' '.implode(', ', $names);
}

There are three argument variants you can use:

InputArgument::REQUIRED

The argument is mandatory. The command doesn't run if the argument isn't provided;

InputArgument::OPTIONAL

The argument is optional and therefore can be omitted. This is the default behavior of arguments;

InputArgument::IS_ARRAY

The argument can contain any number of values. For that reason, it must be used at the end of the argument list.

You can combine IS_ARRAY with REQUIRED or OPTIONAL like this:

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$this
    // ...
    ->addArgument(
        'names',
        InputArgument::IS_ARRAY | InputArgument::REQUIRED,
        'Who do you want to greet (separate multiple names with a space)?'
    )
;

Using Command Options

Unlike arguments, options are not ordered (meaning you can specify them in any order) and are specified with two dashes (e.g. --yell). Options are always optional, and can be setup to accept a value (e.g. --dir=src) or as a boolean flag without a value (e.g. --yell).

For example, add a new option to the command that can be used to specify how many times in a row the message should be printed:

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// ...
use Symfony\Component\Console\Input\InputOption;

$this
    // ...
    ->addOption(
        // this is the name that users must type to pass this option (e.g. --iterations=5)
        'iterations',
        // this is the optional shortcut of the option name, which usually is just a letter
        // (e.g. `i`, so users pass it as `-i`); use it for commonly used options
        // or options with long names
        null,
        // this is the type of option (e.g. requires a value, can be passed more than once, etc.)
        InputOption::VALUE_REQUIRED,
        // the option description displayed when showing the command help
        'How many times should the message be printed?',
        // the default value of the option (for those which allow to pass values)
        1
    )
;

Next, use this in the command to print the message multiple times:

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for ($i = 0; $i < $input->getOption('iterations'); $i++) {
    $output->writeln($text);
}

Now, when you run the command, you can optionally specify a --iterations flag:

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# no --iterations provided, the default (1) is used
$ php bin/console app:greet Fabien
Hi Fabien!

$ php bin/console app:greet Fabien --iterations=5
Hi Fabien!
Hi Fabien!
Hi Fabien!
Hi Fabien!
Hi Fabien!

# the order of options isn't important
$ php bin/console app:greet Fabien --iterations=5 --yell
$ php bin/console app:greet Fabien --yell --iterations=5
$ php bin/console app:greet --yell --iterations=5 Fabien

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$this
    // ...
    ->addOption(
        'iterations',
        'i',
        InputOption::VALUE_REQUIRED,
        'How many times should the message be printed?',
        1
    )
;

Note that to comply with the docopt standard, long options can specify their values after a whitespace or an = sign (e.g. --iterations 5 or --iterations=5), but short options can only use whitespaces or no separation at all (e.g. -i 5 or -i5).

There are four option variants you can use:

InputOption::VALUE_IS_ARRAY

This option accepts multiple values (e.g. --dir=/foo --dir=/bar);

InputOption::VALUE_NONE

Do not accept input for this option (e.g. --yell). The value returned from is a boolean (false if the option is not provided). This is the default behavior of options;

InputOption::VALUE_REQUIRED

This value is required (e.g. --iterations=5 or -i5), the option itself is still optional;

InputOption::VALUE_OPTIONAL

This option may or may not have a value (e.g. --yell or --yell=loud).

You need to combine VALUE_IS_ARRAY with VALUE_REQUIRED or VALUE_OPTIONAL like this:

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$this
    // ...
    ->addOption(
        'colors',
        null,
        InputOption::VALUE_REQUIRED | InputOption::VALUE_IS_ARRAY,
        'Which colors do you like?',
        ['blue', 'red']
    )
;

Options with optional arguments

There is nothing forbidding you to create a command with an option that optionally accepts a value, but it's a bit tricky. Consider this example:

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// ...
use Symfony\Component\Console\Input\InputOption;

$this
    // ...
    ->addOption(
        'yell',
        null,
        InputOption::VALUE_OPTIONAL,
        'Should I yell while greeting?'
    )
;

This option can be used in 3 ways: greet --yell, greet --yell=louder, and greet. However, it's hard to distinguish between passing the option without a value (greet --yell) and not passing the option (greet).

To solve this issue, you have to set the option's default value to false:

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// ...
use Symfony\Component\Console\Input\InputOption;

$this
    // ...
    ->addOption(
        'yell',
        null,
        InputOption::VALUE_OPTIONAL,
        'Should I yell while greeting?',
        false // this is the new default value, instead of null
    )
;

Now it's possible to differentiate between not passing the option and not passing any value for it:

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$optionValue = $input->getOption('yell');
if (false === $optionValue) {
    // in this case, the option was not passed when running the command
    $yell = false;
    $yellLouder = false;
} elseif (null === $optionValue) {
    // in this case, the option was passed when running the command
    // but no value was given to it
    $yell = true;
    $yellLouder = false;
} else {
    // in this case, the option was passed when running the command and
    // some specific value was given to it
    $yell = true;
    if ('louder' === $optionValue) {
        $yellLouder = true;
    } else {
        $yellLouder = false;
    }
}

The above code can be simplified as follows because false !== null:

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$optionValue = $input->getOption('yell');
$yell = ($optionValue !== false);
$yellLouder = ($optionValue === 'louder');