There's an enormous grey area in-between them though, and something that bridges that area can be insanely powerful. Making it easy to go from doing something by hand to fully automating it creates value. It's one of the main strengths of a command line interface.
I wouldn’t call it enormous — Python can be used as an interactive shell (there’s even a toy “operating system” that uses it as the only text shell), and traditional shells can write (simpler) versions of software that’s normally made in Python https://news.ycombinator.com/item?id=23643096
To clarify: I didn't mean the tools, they do indeed overlap in functionality. I meant the activities you refered to, "program my computer" and "interactively command my computer".
