Ask David Korn About ksh And More

David Korn is the author of the famous Korn shell, ksh, which deserves consideration next to the ubiquitous bash. Quote (regarding the AT&T research group he's part of): "We don't write anything in Perl anymore, because [ksh93] has all the functionality built in." He's also an AT&T fellow, and heads up the UWIN project, which "provides a mechanism for building and running UNIX applications on Windows NT, Windows 98, and Windows 95 with few, if any, changes necessary." This is the software that allowed some crazy folks to run GNOME on Windows several weeks back as well. (And is available for no-cost personal use.) This is the same David Korn you may remember from this picture. I met him at a recent NYLUG meeting when he spoke about the Advanced Software Technologies collection of tools, now Open Source, and he graciously agreed to field questions in the usual Slashdot interview style. So please leave your questions in the space below --1 question per comment, please -- and Korn will get back to you with answers in the near future.

Comments

Why Only Unix/Linux?

[north.coaster]

The "shell" has been a key feature of Unix/Linux for over twenty years. The concept of having the freedom to use a different shell is clearly popular and important among users. Do you have any thoughts about why the shell concept has not caught on with other operating systems? I'm thinking of NT and Win2K in particular, but it seems to be true in general.

north.coaster

ksh93 as a programming language?

[Lumpish Scholar]

What are some of the differences between ksh88 (which I think of as comparable to bash or the Posix shell) and ksh93, that makes the latest KornShell as good or better a language than Perl?

You mean this one?

[robinjo]

I've been attending the USENIX NT and LISA NT (Large Installation Systems Administration for NT) conference in downtown Seattle this week.

One of those magical Microsoft moments(tm) happened yesterday and I thought that I'd share. Non-geeks may not find this funny at all, but those in geekdom (particularly UNIX geekdom) will appreciate it.

Greg Sullivan, a Microsoft product manager (henceforth MPM), was holding forth on a forthcoming product that will provide Unix style scripting and shell services on NT for compatibility and to leverage UNIX expertise that moves to the NT platform. The product suite includes the MKS (Mortise Kern Systems) windowing Korn shell, a windowing PERL, and lots of goodies like awk, sed and grep. It actually fills a nice niche for which other products (like the MKS suite) have either been too highly priced or not well enough integrated.

An older man, probably mid-50s, stands up in the back of the room and asserts that Microsoft could have done better with their choice of Korn shell. He asks if they had considered others that are more compatible with existing UNIX versions of KSH.

The MPM said that the MKS shell was pretty compatible and should be able to run all UNIX scripts.

The questioner again asserted that the MKS shell was not very compatible and didn't do a lot of things right that are defined in the KSH language spec.

The MPM asserted again that the shell was pretty compatible and should work quite well.

This assertion and counter assertion went back and forth for a bit, when another fellow member of the audience announced to the MPM that the questioner was, in fact David Korn of AT&T (now Lucent) Bell Labs. (David Korn is the author of the Korn shell)

Uproarious laughter burst forth from the audience, and it was one of the only times that I have seen a (by then pink cheeked) MPM lost for words or momentarily lacking the usual unflappable confidence. So, what's a body to do when Microsoft reality collides with everyone elses?

---Lisa

ksh today

[Y-Leen]

During the design of ksh, were you limited/influenced by computer hardware and consumer market?

Given the chance to completely redesign ksh for today's higher spec mahines and the current consumer base, what new features would you include?

True Story?

[travisd]

Was the story about you embarrasing a Microsoftie at a conference true? Specifically, that he was insisting that their implmentation of ksh in their unix compatibility kit was true to the "real" thing and trying to argue the point with you. The argument ended when somoene else finally stood up and informed the speaker who he was arguing with.

Just curious...

Kind of a shell question...

[update()]

There's a lot of squabbling in the Linux world about how the Unix mentality of small apps communicating through standard input/output to form a pipeline should be maintained in the new whiz-bang, GUI environments. Do you think that it can/should be done? What should be the most important considerations for such a messaging system and how should a standard be established?

So Korn (the band) drinks Coors Light? I might have suspected...

What functionality/code in ksh r u least proud of?

[segmond]

It is very hard to find a programmer who is completely satisified with his code. No matter how happy she is with it, there is always that part which she wishes to improve. As far as ksh is concerned what is it that you wish you didn't do, can improve?

UWIN and etc

[rabtech]

You once said that you had to learn Windows NT because you couldn't criticize what you didn't know. What I'd like to know (as a primarily Windows programmer) is what do you consider to be the best and worst parts of both the Windows NT/2000 model and the UNIX model. What advice can you give? Also, has working on the UWIN project given you any insights that you can share with the rest of the community?
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The IHA Forums

Public Apology

[watanabe]

Dear Dr. Korn, I feel I owe you an apology, and this seemed like a great chance! I went to school with Adam at Brown. And, in 1993, my roommate, Matt Smith, woke me up at about midnight, excitedly telling me "Do you know the Korn Shell? This guy's dad wrote the Korn shell!!!" He was coming in with Adam from somewhere.

I sort of turned over in my sleep, (I was extremely groggy), and said "I hate the Korn shell." and went back to bed. Adam never really talked to me after that, although he was polite enough to me at parties.

So, Dr. Korn, I feel I owe you an apology. I didn't mean to disrespect your lifework in front of your son! I still can't use the korn shell, but call it fear of the unknown, please, rather than lucid comments on your code.

Peter Vessenes, Brown '97

Comparison

[Shadowlion]

Background: the only shell I've ever really used is bash. Bash has always seemed to be the standard UNIX shell (or, at least, the standard default UNIX shell), and for the most part I've always been able to do what I wanted in it.

Question: can you engage in a little unadulterated advocacy for a moment to offer some reasons why an informed user might consider using ksh over bash or other popular UNIX shells? What does ksh provide that other shells don't? Similarly, can you give a realistic appraisal of ksh's drawbacks as compared to bash or other shells?

Thanks.


--

So, Dave ...

[Anonymous Coward]

Quick question: Vi or Emacs?