Adding a Version Option to Your App
===================================

Almost every app out there supports a ``--version`` option of some sort that
provides the end user with version information.  This is pretty important to
include, so we've added an example below.

.. code-block:: python

    from cement.core.foundation import CementApp
    from cement.core.controller import CementBaseController

    VERSION = '0.9.1'

    BANNER = """
    My Awesome Application v%s
    Copyright (c) 2014 John Doe Enterprises
    """ % VERSION

    class MyBaseController(CementBaseController):
        class Meta:
            label = 'base'
            description = 'MyApp Does Amazing Things'
            arguments = [
                (['-v', '--version'], dict(action='version', version=BANNER)),
                ]

    class MyApp(CementApp):
        class Meta:
            label = 'myapp'
            base_controller = MyBaseController


    with MyApp() as app:
        app.run()


This looks like:

.. code-block:: text

    $ python myapp.py --help
    usage: myapp.py (sub-commands ...) [options ...] {arguments ...}

    MyApp Does Amazing Things

    optional arguments:
      -h, --help     show this help message and exit
      --debug        toggle debug output
      --quiet        suppress all output
      -v, --version  show program's version number and exit

    $ python myapp.py --version
    My Awesome Application v0.9.1
    Copyright (c) 2014 John Doe Enterprises