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Re: [Groff] Inserting/importing jpeg photos into groff text?

From: Keith MARSHALL
Subject: Re: [Groff] Inserting/importing jpeg photos into groff text?
Date: Tue, 28 Mar 2006 12:56:41 +0100

>>> Note that some crippled shells (like on Windows) don't allow such
>>> piping; you have to use temporary files instead:
>> Eh???  Standard cmd.exe, or even the older, should be
>> well able handle such a pipe, provided the programs can be found in
>> the PATH.
> OK, fine to hear the opposite.  Thanks.  BTW, how many pipes are
> allowed in a single command?

AFAIK, there's no defined limit.  A practical limitation arises from
the maximum length of the CLI input buffer; with (MS-DOS)
this was a meagre 127 bytes; IIRC, cmd.exe (Win32) allows up to 2048.

Perhaps your confusion arises from the mechanism which MS-DOS used to
implement pipes; temporary files were used to capture the data in the
pipeline, to pass it from one process to the next, because the single
tasking nature of MS-DOS didn't allow all of the pipeline's processes
to coexist.  However, this use of temporary files was transparent to
the user -- it just looked like a pipe, in the UNIX sense.  Win32 is
a fully multitasking OS, so the implementation is now much closer to
the UNIX prototype, but it looks no different to the user.


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