Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!oliveb!apple!well!tneff
From: tneff@well.UUCP (Tom Neff)
Newsgroups: comp.unix.questions
Subject: Re: UNIX prompts (-ksh)
Message-ID: <11134@well.UUCP>
Date: 27 Mar 89 18:06:16 GMT
References: <18805@adm.BRL.MIL> <11080@well.UUCP> <2391@buengc.BU.EDU> <4549@vpk4.UUCP>
Reply-To: tneff@well.UUCP (Tom Neff)
Organization: Whole Earth 'Lectronic Link, Sausalito, CA
Lines: 41

In article <4549@vpk4.UUCP> hjespers@attcan.UUCP (Hans Jespersen) writes:
>In article <2391@buengc.BU.EDU> bph@buengc.bu.edu (Blair P. Houghton) writes:
>>In article <11080@well.UUCP> tneff@well.UUCP (Tom Neff) writes:
>>>Actually not even the classic Korn shell solution of
>>>
>>>	export PS1='$PWD> '
>>>
>>>seems to work everywhere.  
> 
>>I don't know ksh, but all the other shells I've seen use single-quotes
>>to protect against variable substitution...
>
>Absolutely correct. I think Tom ment
>
>	export PS1=`$PWD> `
>                  ^      ^
>---------------------------------------------------------------------------
>Hans Jespersen                UUCP: uunet!attcan!hjespers
>AT&T Canada Inc.                or     ..!attcan!nebulus!arakis!hans
>Toronto, Ontario              #include <std.disclaimer>

Is this a forgery or did an AT&T employee really just suggest using
backquotes in the above example?  The effect would be to attempt to
*execute* the current directory while redirecting stdout nowhere.

Actually the effect would be to set the prompt string to "syntax error"
or some variant thereof. :-)

I repeat, PS1='$PWD> ' -- with single quotes -- works under KornShell
Version 06/03/86d 386 Release 1.2, which is what I run.  On other
systems I have used, you may have to use double quotes instead; under
whatever version of ksh they are running on my distributor's 3b2, not
even that works.  Sometimes the symptom is unwanted early substitution
as alluded to by Jesperson; sometimes you can't get it to interpret in
any form, you just get a $PWD> in your face.  Since ksh source is
available from the toolchest, I assume some versions I encounter have
been built on-site; perhaps there's a touchy spot in the area of the
code that works differently depending on your compiler.  Who knows.
-- 
Tom Neff                  tneff@well.UUCP
                       or tneff@dasys1.UUCP