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 ksh process substitution - which ksh's support this?

In article <01bced5e$dd619580$>,

ksh does not support process substitution on versions of Unix
without the /dev/fd directory.  Bash uses either /dev/fd or
named pipes to implement process substitution, so bash may provide
process substitution on systems where ksh would not.
``The lyf so short, the craft so long to lerne.'' - Chaucer

Chet Ramey, Case Western Reserve University     Internet: c...@po.CWRU.Edu

 Sun, 30 Apr 2000 03:00:00 GMT   
 ksh process substitution - which ksh's support this?

The Bolsky & Korn book "The KornShell", page 326, under "Possible
Extensions", describes process substitution as being available only
on versions of UNIX that support the /dev/fd directory for naming
open files.  With words like this I would not rely on it being
available for use in a portable script.

  -- Conrad

In article <01bced5e$dd619580$>, "Simon Taylor" <> writes:
|> I have written some ksh scripts that need to be portable across a number
|> of Unixes.
|> To my dismay, I have discovered that the process substitution feature
|> I have in my SCO "Open Server 5" ksh (and in the GNU bash), is not
|> available in the ksh shipped with most of the other Unixes I have
|> access to.
|> Is this just because these machines happen to be a few years old,
|> and the newer ksh simply isn't on them, or is process substitution
|> not supported universally?
|> It is particularly important for me to discover whether this feature
|> is supported in the latest Digital Unix, as it is not present in v4.0
|> of the OS.
|> ie: With a shell that supports process substitution one can, for instance,
|> place a process in the context where a file name is
|> expected. As a trivial example:
|>     wc <(ls)
|> will return the word count of the output of the ls command, as if
|> the output were a file.
|> Regards,
|> --
|> Simon Taylor ( - remove the "X"s to reply)
|> Unisolve Pty Ltd         Melbourne, Australia

Conrad Kimball           | Client Server Tech Svcs, Boeing Information & Supt. | P.O. Box 24346, MS 7M-HC
(425) 865-6410           | Seattle, WA  98124-0346

 Mon, 01 May 2000 03:00:00 GMT   
 ksh process substitution - which ksh's support this?

Process substitution is not supported on all versions of UNIX. This feature
is usually only available on versions of the UNIX operating system that
support the /dev/fd directory for naming open files.

Digital UNIX does not support /dev/fd. Neither do a number of other
UNIX operating systems.


 Tue, 02 May 2000 03:00:00 GMT   
   [ 3 post ] 

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