If your program / tool mainly operates on lines of text, you absolutely must check out dmenu <http://tools.suckless.org/dmenu/>.
You can write a program launcher, ssh launcher, file manager, music player, copy to clipboard, password vault, Wifi selector, todo/calendar app, web bookmarks manager, list email headlines, mount volumes, kill processes... All with a bunch of simple shell scripts and stdio. I would say this is the most UNIX-y way to do a GUI. K.
