X-Spam-Check-By: sourceware.org
Date: Mon, 28 Aug 2006 17:25:24 -0400 (EDT)
From: Igor Peshansky <pechtcha AT cs DOT nyu DOT edu>
Reply-To: cygwin AT cygwin DOT com
To: "Silva, Russell" <rsilva AT rsasecurity DOT com>
cc: cygwin AT cygwin DOT com
Subject: Re: Problem when using variable assignment, backticks in shell script
In-Reply-To: <017630AA6DF2DF4EBC1DD4454F8EE29708D75075@rsana-ex-hq1.NA.RSA.NET>
Message-ID: <Pine.GSO.4.63.0608281721230.10073@access1.cims.nyu.edu>
References: <017630AA6DF2DF4EBC1DD4454F8EE29708D75075 AT rsana-ex-hq1 DOT NA DOT RSA DOT NET>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
Precedence: bulk
List-Unsubscribe: <mailto:cygwin-unsubscribe-archive-cygwin=delorie DOT com AT cygwin DOT com>
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com

On Mon, 28 Aug 2006, Silva, Russell wrote:

> I am having a problem using Cygwin, variable assignment, and backticks
> when shell scripting.  Occasionally, variables assigned using a
> backticked expression are not properly assigned; they are left empty.
> The problem appears to be non-deterministic.
>
> For instance, take this script:
> [snip <bug_reproduce.sh>]
>
> A few times out of the 1000 possible, the error code is reached:
>
> $ ./bug_reproduce.sh
> error attempt 245: "" is not the correct string "liars"

Is the error string always empty?  That would indicate to me that bash
somehow failed to launch the child process...  FWIW, bash retains the
exit code of the launched program in $? after a backtick assignment -- try
printing that out and see if there is a correlation.  Also, check the
output on stderr -- perhaps there's an error message printed?
	Igor
-- 
				http://cs.nyu.edu/~pechtcha/
      |\      _,,,---,,_	    pechtcha AT cs DOT nyu DOT edu | igor AT watson DOT ibm DOT com
ZZZzz /,`.-'`'    -.  ;-;;,_		Igor Peshansky, Ph.D. (name changed!)
     |,4-  ) )-,_. ,\ (  `'-'		old name: Igor Pechtchanski
    '---''(_/--'  `-'\_) fL	a.k.a JaguaR-R-R-r-r-r-.-.-.  Meow!

"Las! je suis sot... -Mais non, tu ne l'es pas, puisque tu t'en rends compte."
"But no -- you are no fool; you call yourself a fool, there's proof enough in
that!" -- Rostand, "Cyrano de Bergerac"

--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/