First, of course, came the CLUI (well, first came the punch card and switches, but you have to start somewhere, because before that there were slide rules), then people build a GUI front-end. Then, a while later, apps started drifting back to the CLUI (most notably the web browser which, graphical as it may be, usually starts out with someone typing in a URL).

Now, with desktop UNIX OSes proliferating, CLUI and GUI are getting mixed together (much as they were in the early days of the Jeckell/Hyde DOS/Windows), with users switching back and forth between a terminal window and a graphical app.

With KDE and Gnome (and more to the point, X-windows) on Unix boxes, graphical applications often were created simply to act as friendly front-ends to command-line programs. One of my hopes for Mac OS X was that it would do the same, maintaining all the Mac programs out there, but allowing for a whole lot of new front-ends to powerful UNIX command-line tools.

Leapfrogging the hand-coding of these kinds of tools is ShellShell for OS X. It lets a user/programmer (the line's really getting blurred. Umm. 'scripter'?) create a config script for a command line tool (in the example given at the site, 'cal') to create a graphical front-end for it.

The author envisions a whole suite of these mini-front-ends for popular UNIX commands. I think it's really cool, though I'll be far more impressed if they come up with an intuitive way to handle piping results from one tool to another.