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From: c188-bl@katerina.uucp (Steven Brian McKechnie Sargent)
Newsgroups: comp.unix.wizards
Subject: Re: Redirecting shell output.
Message-ID: <4445@zen.berkeley.edu>
Date: Sun, 18-Oct-87 21:42:17 EDT
Article-I.D.: zen.4445
Posted: Sun Oct 18 21:42:17 1987
Date-Received: Tue, 20-Oct-87 01:34:39 EDT
References: <289@minya.UUCP>
Sender: news@zen.berkeley.edu
Reply-To: sarge@scam.Berkeley.EDU (Steven Brian McKechnie Sargent)
Organization: University of California, Berkeley
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Try the "exec" command of the Shell.  The full syntax is
	exec [command] [redirections]
[Redirections] is optional, in which case [command] runs with the default I/O;
what most people don't know is that [command] is also optional, in which
case [redirections] are applied to the running shell.  So if you say words
like
	exec 2>thump
all standard-error redirections go to a file named "thump."  Saying words like
	exec 14 >&2
	exec 2>thump
will save the old value of 2 in 14, redirect 2 into "thump."  Later you can
undo this with
	exec 2>&14
	exec 14>&-
which restores 2 from 14 and then closes 14.

All this is documented in sh(1), but so tersely that you can skip right over
it and never notice.

S.