From owner-freebsd-hackers  Fri May 23 20:21:00 1997
Return-Path: <owner-hackers>
Received: (from root@localhost)
          by hub.freebsd.org (8.8.5/8.8.5) id UAA03048
          for hackers-outgoing; Fri, 23 May 1997 20:21:00 -0700 (PDT)
Received: from bitbox.follo.net (bitbox.follo.net [194.198.43.36])
          by hub.freebsd.org (8.8.5/8.8.5) with ESMTP id UAA03040
          for <hackers@freebsd.org>; Fri, 23 May 1997 20:20:57 -0700 (PDT)
Received: (from eivind@localhost) by bitbox.follo.net (8.7.6/8.7.3) id FAA05443; Sat, 24 May 1997 05:20:40 +0200 (MET DST)
Date: Sat, 24 May 1997 05:20:40 +0200 (MET DST)
Message-Id: <199705240320.FAA05443@bitbox.follo.net>
From: Eivind Eklund <perhaps@yes.no>
To: Steve Howe <un_x@anchorage.net>
In-reply-to: Steve Howe's message of Fri, 23 May 1997 17:19:30 -0800 (AKDT)
Subject: Re: pipelines
References: <Pine.BSF.3.95q.970523171443.13536A-100000@aak.anchorage.net>
Cc: hackers@freebsd.org
Sender: owner-hackers@freebsd.org
X-Loop: FreeBSD.org
Precedence: bulk


I've kept hackers on the Cc: line - if you reply to this, consider
moving it to -questions.  Thanks.
 
> #!/bin/sh
> # invoke with dummy args ...
> while [ $1 ]; do t=$(($t + 1)); shift; done | cat; echo X$t
> 
> 
> is there any way to find the value of a variable that is set in a pipe
> ... outside the pipe?  i wish i could echo "t"s value in the example
> above, but exporting, etc, doesn't seem to help. 

No possible, AFAIK.  Your '| cat' makes a sub-shell, which can't change
the variables of the parent.  Could you drop it?  Otherwise (probably
with your subject-line :-), you'll have to use temp-files, ie.

#!/bin/sh
# invoke with dummy args ...

umask 77
if mkdir /tmp/dummy.$$
then
	export MYCOUNTER=/tmp/dummy.$$/counter
	echo -n 0 > $MYCOUNTER
	while [ $1 ]
	do
		echo -n $((`cat $MYCOUNTER` + 1)) > $MYCOUNTER
		shift
	done | cat
	echo X`cat $MYCOUNTER`
	rm -rf /tmp/dummy.$$
else
	echo "Unable to create temporary directory /tmp/dummy.$$!"
	exit 1
fi

mkdir is to get secure temp-files.

> please respond directly - i don't subscribe to hackers ...  thanks.

And you shouldn't post this there - it belong in -questions.

Eivind.