[bediger]

If I might rephrase geophile, above: a command line (most of them, anyway) has a grammar, complete with flow-of-control constructs like if-then-else, while loops, for-loops.

You can express more with a grammar than without one. For example, you can express palindrome strings with a grammar, you can't with regular expressions.

We can tail off into philosophy by talking about "generative grammars" allowing you to create new ideas, and this may be what geophile says about "[G]UI is great if it does exactly what you want it to do. But if not, and you want to customize at all, you're stuck." I agree with this sentiment.