I would argue all command line tools have a UI, even if it's just a textual one (consisting of command line parameters, maybe a text prompt, or in rare cases ev

I would argue all command line tools have a UI, even if it's just a textual one (consisting of command line parameters, maybe a text prompt, or in rare cases even an ncurses interface). When I develop command line tools I always think about the UX the user will have.