Applyed suggestions from @fabpot and @stof

Author: dcsg

components/console/changing_default_behavior.rst

@@ -0,0 +1,67 @@
+.. index::
+   single: Console; Changing the Default Command
+
+Changing the Default Command
+============================
+
+.. versionadded:: 2.5,
+    The :method:`Symfony\\Component\\Console\\Application::setDefaultCommand`
+    method was introduced in version 2.5.
+
+By default the Application will always run the ``ListCommand``. In order to change
+the default command you just need to pass the command name you want to run by
+default to the ``setDefaultCommand`` method::
+
+    namespace Acme\Command;
+
+    use Symfony\Component\Console\Command\Command;
+    use Symfony\Component\Console\Input\InputInterface;
+    use Symfony\Component\Console\Output\OutputInterface;
+
+    class HelloWorldCommand extends Command
+    {
+        protected function configure()
+        {
+            $this->setName('hello:world')
+                ->setDescription('Outputs \'Hello World\'');
+        }
+
+        protected function execute(InputInterface $input, OutputInterface $output)
+        {
+            $output->writeln('Hello World');
+        }
+    }
+
+Executing the application and changing the default Command::
+
+    // application.php
+
+    use Acme\Command\HelloWorldCommand;
+    use Symfony\Component\Console\Application;
+
+    $command = new HelloWorldCommand();
+    $application = new Application();
+    $application->add($command);
+    $application->setDefaultCommand($command->getName());
+    $application->run();
+
+Test the new default console command by running the following
+
+.. code-block:: bash
+
+    $ php application.php
+
+This will print the following to the command line:
+
+.. code-block:: text
+
+    Hello Fabien
+
+.. tip::
+
+    The feature was a limitation since you cannot use the Command ``arguments``.
+
+Learn More!
+-----------
+
+* :doc:`/components/console/single_command_tool`

components/console/changing_default_command.rst

@@ -6,6 +6,7 @@ Console
 
     introduction
     usage
-    changing_default_behavior
+    changing_default_command
+    single_command_tool
     events
     helpers/index

components/console/index.rst

@@ -525,7 +525,8 @@ Learn More!
 -----------
 
 * :doc:`/components/console/usage`
-* :doc:`/components/console/changing_default_behavior`
+* :doc:`/components/console/single_command_tool`
+* :doc:`/components/console/changing_default_command`
 
 .. _Packagist: https://packagist.org/packages/symfony/console
 .. _ANSICON: https://github.com/adoxa/ansicon/downloads

components/console/introduction.rst

@@ -1,4 +1,72 @@
+.. index::
+single: Console; Single command application
+
 Building a Single Command Application
 =====================================
 
-This Document was moved to :doc:`/components/console/changing_default_behaviour`
+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. Fortunately,
+it is possible to remove this need by extending the application::
+
+    namespace Acme\Tool;
+
+    use Symfony\Component\Console\Application;
+    use Symfony\Component\Console\Input\InputInterface;
+
+    class MyApplication extends Application
+    {
+        /**
+         * Gets the name of the command based on input.
+         *
+         * @param InputInterface $input The input interface
+         *
+         * @return string The command name
+         */
+        protected function getCommandName(InputInterface $input)
+        {
+            // This should return the name of your command.
+            return 'my_command';
+        }
+
+        /**
+         * Gets the default commands that should always be available.
+         *
+         * @return array An array of default Command instances
+         */
+        protected function getDefaultCommands()
+        {
+            // Keep the core default commands to have the HelpCommand
+            // which is used when using the --help option
+            $defaultCommands = parent::getDefaultCommands();
+
+            $defaultCommands[] = new MyCommand();
+
+            return $defaultCommands;
+        }
+
+        /**
+         * Overridden so that the application doesn't expect the command
+         * name to be the first argument.
+         */
+        public function getDefinition()
+        {
+            $inputDefinition = parent::getDefinition();
+            // clear out the normal first argument, which is the command name
+            $inputDefinition->setArguments();
+
+            return $inputDefinition;
+        }
+    }
+
+When calling your console script, the command ``MyCommand`` will then always
+be used, without having to pass its name.
+
+You can also simplify how you execute the application::
+
+    #!/usr/bin/env php
+    <?php
+    // command.php
+    use Acme\Tool\MyApplication;
+
+    $application = new MyApplication();
+    $application->run();