[kevinh456]

There are so many things worth learning on unproductive time that making myself marginally more productive with an esoteric command line tool actually isn't the greatest value proposition. VIM, for instance, is my preferred editor. It's on every Unix machine I need. I learned a ton of basic things I can do with it. I don't customize it because I don't usually have the permissions or the time. It lets me get in, edit, get out. You have to judge the reason for a tool.

Personally, the best tool for typing productivity I ever have used is a keyboard with no letters on the key caps. It also means I'm the only person in my immediate circle that can use my computer at all. My wife literally can't use my PC.