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To: bugs@freebsd.org
Subject: bug in /bin/sh for loops
Date: Fri, 27 Oct 95 03:06:55 PDT
From: Ben Jackson <bjj@sequent.com>
Sender: owner-bugs@freebsd.org
Precedence: bulk

[FreeBSD 2.1.0 951005-SNAP]

The appended shell script doesn't have the expected output.  The first
half executes a loop which prints 0, 1, 2.  The second half introduces
a simple background job during each loop iteration.  It seems that at
the point where you run a background job in a { } list, the shell forks
and the rest of the {} list runs in the new shell.  This results in the
value of VAR being lost (hence output 0,0,0) and having the main shell
exit before the loop finishes running.  All of the other shell-local
information is also lost (jobs list, etc).  Every other shell that
claimed Bourne shell compatibility (zsh, ksh, AT&T sh) that I tried it
on did what you'd expect.

--Ben

VAR=0
for X in 1 2 3
do
	echo $VAR
	VAR=$X
done

VAR=0
for X in 1 2 3
do
	echo $VAR
	VAR=$X
	/bin/ls > /dev/null &
done