Flowchart

+-------------+     +-----------+     +------------+     +-----------+
| Read Input  |---->| Parse     |---->| Execute    |---->| Display   |
|             |     | Command   |     | Command    |     | Result    |
+-------------+     +-----------+     +------------+     +-----------+
        ^                                                      |
        |                                                      |
        +------------------------------------------------------+