Why Different Shells?

[vinot85]

Hi friends,

I need to know why UNIX systems are having different types of shells like Bourne, Korn, C, Tcsh..etc?Why Cant the Operating system can work and interpret thew user commands using a single Shell? What is the need of different Shells in the same system?

[Nepomuk]

Hi friends,

I need to know why UNIX systems are having different types of shells like Bourne, Korn, C, Tcsh..etc? Why Cant the Operating system can work and interpret the user commands using a single Shell? What is the need of different Shells in the same system?

The thing is, that a Shell is just a program, which wraps itself around many basic components of the system to allow communication. Somebody thought of one, then somebody else thought "I can make a better one", somebody third thought "Hm, I don't like that thing about shell xyz." or "I'd like some additional feature..." and so many different shells were written. These shells were designed for different needs and are preferred by different people.

Under Linux systems, bash is the most common shell nowadays, but you get various other shells included in the system too. I guess, it's similar with Unix.

It can be quite annoying at times, that you have to think about so many shells when writing some code, but you can't change it and, luckily, a lot of shells are similar in many aspects.

Greetings,
Nepomuk