CLUI: Building a Graphical Command Line has a nice article on using the command-line for graphical programs. It goes into some good discussion on the command-line and GUI interfaces and how they differ and what each expects. It's very interesting if you've never thought about it before.

It was this article that got me started on cmd/cmd2 in Python, as I just wanted to use the command-line and didn't care to use it as a gui.

Project Idea

Now, I have an actual use case for it -- use this to be able to access and create journal entries for jrnl on my iPad/iPhone or on the web as needed.