> This is one area where there are hundreds of different shells out there... Most never go beyond pet projects though. I have had the same experience. For ev

> This is one area where there are hundreds of different shells out there... Most never go beyond pet projects though. I have had the same experience. For every scripting/interpreted language out there, there is at least one person who thinks "ooh, wouldn't it be neat if I could use this as a shell?" or, almost as often, "to program my text editor?" Soon they realize that interactive programs like shells and text editors are hard to get right. There are thousands of special cases and non-obvious features that have only been found by hard experience. These programs must also interact with a computing world that has evolved over decades. Most programmers give up at this point. A few persist, and of those, a few end up creating something genuinely useful to more than themselves and a couple of friends. I'm not sure if I would call shells a "solved" problem, but I don't believe the incredible amount of work required to make a sufficiently better one is worth it.