def _get_help_command_preface(command_name='scenedetect'):
    """Preface/intro help message shown at the beginning of the help command."""
    return """
The PySceneDetect command-line interface is grouped into commands which
can be combined together, each containing its own set of arguments:

 > {command_name} ([options]) [command] ([options]) ([...other command(s)...])

Where [command] is the name of the command, and ([options]) are the
arguments/options associated with the command, if any. Options
associated with the {command_name} command below (e.g. --input,
--framerate) must be specified before any commands. The order of
commands is not strict, but each command should only be specified once.

Commands can also be combined, for example, running the 'detect-content'
and 'list-scenes' (specifying options for the latter):

 > {command_name} -i vid0001.mp4 detect-content list-scenes -n

A list of all commands is printed below. Help for a particular command
can be printed by specifying 'help [command]', or 'help all' to print
the help information for every command.

Lastly, there are several commands used for displaying application
version and copyright information (e.g. {command_name} about):

    help:    Display help information (e.g. `help [command]`).
    version: Display version of PySceneDetect being used.
    about:   Display license and copyright information.
""".format(command_name=command_name)