Bruce Park <bpark79@hotmail.com> [2002-11-10 16:33:19 -0500]: > > After doing some research, I found out that ash is a clone of a bourne > shell from BSD. Yes. But it is a modern clone and has all of the modern features and is very standards conforming. But it is not the old Bourne shell. > I was using this last night and I really couldn't find anything that > differs from the real shell. Okay, now we get into existentialism. What is real? And besides, if you are asking these questions then we both know you are just beginning. As a beginner you should not be able to tell the difference between the shells. The differences are subtle and you would need to be more expert in the shells before you ran into the differences. > Now, what can I do about the C shell and the Korn shell? Are those > also not free? The C-shell is free. On debian you can install either it or tcsh or both. If you only have one of them that one will be the csh. If both then the bsd-csh will be the csh. apt-cache show tcsh apt-cache show csh The Korn shell is not free. At one time you could buy source from AT&T by an anonymous uucp connection for IIRC $300 and we did that. Anonymous uucp, ah, those were the days. Not! In any case there is a ksh clone called pdksh the public domain ksh. Having used ksh a lot I find that pdksh is not quite the same as the real ksh from a command line shell point of view. But I don't use it much anymore in favor of bash. apt-cache show pdksh > I'm doing a lot of shell scripting and people are saying that C > wasn't designed for it. Well, it [C-shell] was designed for it. But the designers failed severely and have been bearing the brunt of the frustrations of the net for problems with the design ever since. I recommend you don't use it for scripting. It will frustrate you and annoy your users. Even if you don't see the bugs your users will. Messages like "toshort: out of space" mean someone has an enviroment variable longer than the static buffer size and other cryptic problems. (That is from memory and I probably got it wrong but you get the idea.) [When I last used csh I thought it was the best command line shell for paper terminals that I had ever used. Specifically you had all of the command numbers there on paper ready for you to repeat whenever you wanted. That was in the late 1980's when paper terminals were still in vogue. But times have changed.] > I'm sure they are right because I'm reading about it and it says > that bourne shell scripts are the best since they run faster than > C. They probably meant faster than C-shell, not faster than C the compiled language. They have similar names and share a small amount of syntax but are not otherwise more or less related than bash is to the C compiled language. It will only confuse people to call C-shell C, as in the compiled language. But speed of shell execution is generally not important. Pay no attention to those arguments. That is not a reason to use one shell over another. I would optimize your time of writing the program over execution time. I would avoid csh because it has frustrating limitations. > In reality, I problably would use Perl to do everything but right > now, the focus is on learning each individual shell to see how and > why they differ. A worthy goal. Install all, play, learn. As long as you are learning you might want to look into 'ruby'. Add it to your list. It is similar to perl in many ways but with a clean syntax and it is very object oriented. Ruby is coming as a new wave to the interpreted programming language scene. Do a google search and you will find many articles and programming tutorials on the web. apt-cache show ruby Enjoy, Bob
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