Edit: Unfortunately, the images originally included in this post are gone, because of hosting problems in late 2009. My apologies.
I think I may have found the program that actually does the least I’ve ever seen … short of things like cowsay. I forget what I was looking for, but I installed gmrun last night and tried it. This is what I got.
If you type in the executable for a program there, it starts. Genius, isn’t it? It’s essentially a program that runs other programs. And that’s all.
I apologize if I sound a little snide. I wish I had thought of the idea first, to tell the truth. And really, it’s not as redundant as it sounds. Like most really great, really flexible, really useful programs, this one is terribly deceptive. For one thing, if you wire it to the Alt-F2 key, as most people probably will, you get quicker and faster access to programs than, for example, wading through nested menus.
So in that sense it’s a half-step between a terminal window — which as we all know, is an amazing and powerful utility, right? — and an actual full-featured GUI application.
It gets better. gmrun does a few things you wouldn’t guess without delving deeper. It keeps a command history (a feature I generally do not consider a feature, but some do), and it will do command-line completion. You can precisely and perfectly trigger the window in an exact location.
It also can trigger terminal windows at a keystroke, default on a command to spawn a terminal window (in other words, you type htop, it triggers a terminal with htop inside it), and a bunch of neat other things. If you give it a URL, it can detect that and open it in a browser, instead of acting confused.
Take a look here for an idea of its potential. And the moral of the story, of course, is that you can’t judge a program by its interface.