picocli

## Class CommandLine.HelpCommand

- java.lang.Object
- - picocli.CommandLine.HelpCommand

- All Implemented Interfaces:
    Runnable, CommandLine.IHelpCommandInitializable
  Enclosing class:
    CommandLine

      public static final class CommandLine.HelpCommand
      extends Object
      implements CommandLine.IHelpCommandInitializable, Runnable

  Help command that can be installed as a subcommand on all application commands. When invoked with a subcommand argument, it prints usage help for the specified subcommand. For example:

       // print help for subcommand
       command help subcommand

  When invoked without additional parameters, it prints usage help for the parent command. For example:

       // print help for command
       command help

  For internationalization: this command has a `--help` option with `descriptionKey = "helpCommand.help"`, and a `COMMAND` positional parameter with `descriptionKey = "helpCommand.command"`.
  Since:
    3.0

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `HelpCommand()`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `init(CommandLine helpCommandLine, CommandLine.Help.Ansi ansi, PrintStream out, PrintStream err)` Initializes this object with the information needed to implement a help command that provides usage help for other commands.
    `void` | `run()` Invokes `usage` for the specified command, or for the parent command.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### HelpCommand

          public HelpCommand()

  - ### Method Detail

    - #### run

          public void run()

      Invokes `usage` for the specified command, or for the parent command.
      Specified by:
        `run` in interface `Runnable`

    - #### init

          public void init(CommandLine helpCommandLine,
                           CommandLine.Help.Ansi ansi,
                           PrintStream out,
                           PrintStream err)

      Initializes this object with the information needed to implement a help command that provides usage help for other commands.
      Specified by:
        `init` in interface `CommandLine.IHelpCommandInitializable`
      Parameters:
        `helpCommandLine` - the `CommandLine` object associated with this help command. Implementors can use this to walk the command hierarchy and get access to the help command's parent and sibling commands.
        `ansi` - whether to use Ansi colors or not
        `out` - the stream to print the usage help message to
        `err` - the error stream to print any diagnostic messages to, in addition to the output from the exception handler

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