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# 1  
Old 12-19-2001
different shell programs,processes

Hi,
why do we have 3 types of shell programs.

I read that the k-shell is supposed to be the latest replacement of the Bourne shell with additional features. But why call it K-shell when one can call it as a different version of Bourne shell say bourne2.

what do we have the C shell for?

Is there any limit for the number of processes that can be run simultaneously ?

Thanks
# 2  
Old 12-19-2001
Well, the /bin/sh shell (Bourne Shell) is a derivitave of the original Unix shell, at Bell Labs. The ksh (Korn Shell, written by David Korn) is a much more full featured shell that is, for the most part, backwards compatible with modern versions of the Bourne shell. Then on most Linux systems, we have bash - the Bourne Again SHell... It contains many of the best features from all shells, without using all the wonderfull features of each.
The csh is (from my point of view) another flavor; a choice. From those damn Berkely hippie-folks (just kidding - kinda).

There are many other shells out there, but they are probably the most common. There is the Perl shell, the Posix shell (usually just called "sh", like the bourne shell), several stripped down shells, and public domain / open source clone of each of them...

As far as concurrent process limits, It would most likely matter on what Unix you are using, and how it's configured (to keep a single person from consuming all resources for the machine), but theoretically, most will allow a little over 32,000 concurrent processes.

I think this is all generally correct, but I wouldn't take this as gospel - especially not from me.

Hope that helps.
 

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