Very Computer

It is found that the read Public domain version of ksh can't read variable
from pipe ...

i.e.

# A="Hello"
# echo $A | read B
# echo $B

However, I found that the above syntax was correctly in commercial version
of ksh like AIX and Solaris..

Do any one have idea on how to solve this problem?

Thanks!

Henry

        What is $bar after,     echo foo | read bar?

        The is foo.  ksh runs the last component of a pipeline
        in the current process.  Some shells run it as a subshell
        as if you had invoked it as  echo foo | (read bar).

Quote:> However, I found that the above syntax was correctly in commercial version
> of ksh like AIX and Solaris..

> Do any one have idea on how to solve this problem?

A workaround is to put read B and echo $B into the same subshell by using a
compound command block (or a subshell bracket)...

echo $A | { read B; echo $B; }

Quote:> Thanks!

> Henry

--
The wind doth taste so bitter sweet,
        Like Jaspar wine and sugar,
It must have blown through someone's feet,
        Like those of Caspar Weinberger.                -- P. Opus

=Brian

: > # echo $A | read B
: > ...
:
: Just to expound upon the previous threads: this behavior
: peculiar to ksh(1) and ksh93(1) is a consequence of executing
: the last component of a pipe in a "new process environment",
: and not a new (forked) process, as a speed optimization. Relying
: on this behavior is officially deprecated, as Korn & Bolsky
: state in both editions of their book, and "may disappear at
: any time."
:
: =Brian
:

That's nor going to happen,  as that feature is the main reason to
use Korn shell over other shells,  and has been incorporated into
other vendor's posix shells,  like HP-UX.  Its removal would likely cause
the failure of 80% of all ksh scripts.

Please don't spread FUD - leave that to M$.

Dan Mercer

Well of course you are accurate -- if not "correct".... I am
well aware that 5% of all posts in C.U.S. devolves to this very
issue ;) I couldn't locate this in a quick scan in the FAQ
though -- it should be one!

Please please don't hate me; I'm just reporting the facts.

Quote:> Please don't spread FUD - leave that to M$.

=Brian ("Don't tell A.C. that I post via Google Groups.")

: > > > "may disappear at any time."
:
: > That's nor going to happen,  as that feature is the main reason to
: > use Korn shell over other shells,  and has been incorporated into
: > other vendor's posix shells,  like HP-UX.  Its removal would likely cause
: > the failure of 80% of all ksh scripts.
:
: Mr. M, it's _me_, Brian! I _know_ that you know what
: I should be knowing, especially about this matter!
:
: Well of course you are accurate -- if not "correct".... I am
: well aware that 5% of all posts in C.U.S. devolves to this very
: issue ;) I couldn't locate this in a quick scan in the FAQ
: though -- it should be one!
:
: Please please don't hate me; I'm just reporting the facts.
:
: > Please don't spread FUD - leave that to M$.
:
: BTW, What's "FUD"? "Fractious Ulcerating Discourse"?
Fear - Uncertainty - Doubt - a business tactic pioneered by
IBM that came to light in the CDC lawsuit,  a practice
wholeheartedly adopted by M$.

Dan Mercer

:
: =Brian ("Don't tell A.C. that I post via Google Groups.")
:

http://home.comcast.net/~j.p.h/cus-faq-2.html#33

It could probably do with some enhancement (in fact, it may be wrong
in a couple places), and maybe the question should be made broader to
include this kind of thing.

Joe
--
Gort, klatu barada nikto