--- /dev/null
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Console\Command;
+
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputOption;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+use Symfony\Component\Console\Output\Output;
+use Symfony\Component\Console\Command\Command;
+
+/**
+ * HelpCommand displays the help for a given command.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class HelpCommand extends Command
+{
+ private $command;
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function configure()
+ {
+ $this->ignoreValidationErrors();
+
+ $this
+ ->setName('help')
+ ->setDefinition(array(
+ new InputArgument('command_name', InputArgument::OPTIONAL, 'The command name', 'help'),
+ new InputOption('xml', null, InputOption::VALUE_NONE, 'To output help as XML'),
+ ))
+ ->setDescription('Displays help for a command')
+ ->setHelp(<<<EOF
+The <info>%command.name%</info> command displays help for a given command:
+
+ <info>php %command.full_name% list</info>
+
+You can also output the help as XML by using the <comment>--xml</comment> option:
+
+ <info>php %command.full_name% --xml list</info>
+EOF
+ )
+ ;
+ }
+
+ /**
+ * Sets the command
+ *
+ * @param Command $command The command to set
+ */
+ public function setCommand(Command $command)
+ {
+ $this->command = $command;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function execute(InputInterface $input, OutputInterface $output)
+ {
+ if (null === $this->command) {
+ $this->command = $this->getApplication()->get($input->getArgument('command_name'));
+ }
+
+ if ($input->getOption('xml')) {
+ $output->writeln($this->command->asXml(), OutputInterface::OUTPUT_RAW);
+ } else {
+ $output->writeln($this->command->asText());
+ }
+
+ $this->command = null;
+ }
+}