$COMMAND
$COMMAND menu

  Show the menu.

$COMMAND verify [ARGS...]

  Verify the currently selected problem with ARGS.

$COMMAND run [ARGS...]

  Run the currently selected problem with ARGS.
  Not all problems support `run`.

$COMMAND solution

  Show the solution for the currently selected problem.

$COMMAND print

  Print the text of the currently selected level.

$COMMAND selected

  Print the name of the currently selected level.
 
$COMMAND select LEVEL

  Set the currently selected LEVEL.

$COMMAND list

  List the available levels.

$COMMAND next

  Select the next adventure.

$COMMAND prev

  Select the previous adventure.

$COMMAND completed

  List the completed levels.
 
$COMMAND reset

  Reset the list of completed levels.

$COMMAND help

  Show this message.