From: 71231 DOT 104 AT compuserve DOT com (Richard Slobod)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: shell scripts in DJGPP
Date: Wed, 09 Feb 2000 23:13:10 GMT
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In article <Pine DOT SUN DOT 3 DOT 91 DOT 1000209090102 DOT 9816G-100000 AT is>,
  Eli Zaretskii <eliz AT is DOT elta DOT co DOT il> wrote:

> That's not surprising: the problems with redirection from a batch file
> are a misfeature of COMMAND.COM, caused by the fact that it doesn't
> spawn another copy of itself to run the batch.

If COMMAND.COM spawned a new shell to run batch files, it would (1)
waste precious conventional memory (and note that batch files are often
used to launch application programs which might need that memory), (2)
make it impossible to permanently set environment variables from a batch
file, and (3) make it unsafe to start TSR programs from a batch file.

For that matter, this behavior doesn't really prevent I/O redirection
with batch files; it just complicates implementing it a bit and
Microsoft didn't bother to go to the trouble.  Note that 4DOS works the
same way and it manages redirection with batch files just fine.


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