From owner-freebsd-questions@FreeBSD.ORG  Mon Jan 12 03:53:03 2009
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Delivered-To: freebsd-questions@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id A7E48106566C
	for <freebsd-questions@freebsd.org>;
	Mon, 12 Jan 2009 03:53:03 +0000 (UTC)
	(envelope-from freebsd@optimis.net)
Received: from mail.optimis.net (mail.optimis.net [69.104.191.124])
	by mx1.freebsd.org (Postfix) with ESMTP id 7B6FB8FC12
	for <freebsd-questions@freebsd.org>;
	Mon, 12 Jan 2009 03:53:03 +0000 (UTC)
	(envelope-from freebsd@optimis.net)
Received: from marvin.optimis.net (marvin.optimis.net [192.168.1.3])
	by mail.optimis.net (8.14.2/8.14.2) with ESMTP id n0C3EUWj031223
	for <freebsd-questions@freebsd.org>;
	Sun, 11 Jan 2009 19:14:30 -0800 (PST)
	(envelope-from freebsd@optimis.net)
Received: from marvin.optimis.net (localhost [127.0.0.1])
	by marvin.optimis.net (8.14.2/8.14.2) with ESMTP id n0C3ETuU047578
	for <freebsd-questions@freebsd.org>;
	Sun, 11 Jan 2009 19:14:29 -0800 (PST)
	(envelope-from freebsd@optimis.net)
Received: (from george@localhost)
	by marvin.optimis.net (8.14.2/8.14.2/Submit) id n0C3ETjP047577
	for freebsd-questions@freebsd.org; Sun, 11 Jan 2009 19:14:29 -0800 (PST)
	(envelope-from freebsd@optimis.net)
Date: Sun, 11 Jan 2009 19:14:29 -0800
From: George Davidovich <freebsd@optimis.net>
To: freebsd-questions@freebsd.org
Message-ID: <20090112031429.GA42596@marvin.optimis.net>
References: <7740275E-77AA-45C1-B95E-C1F62D2AAB29@goldmark.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <7740275E-77AA-45C1-B95E-C1F62D2AAB29@goldmark.org>
User-Agent: Mutt/1.5.18 (2008-05-17)
Subject: Re: bash versus sh test builtin
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-questions>
List-Post: <mailto:freebsd-questions@freebsd.org>
List-Help: <mailto:freebsd-questions-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 12 Jan 2009 03:53:03 -0000

On Sun, Jan 11, 2009 at 08:08:18PM -0600, Jeffrey Goldberg wrote:
> The -ne operator for [ in /bin/sh doesn't seem to work as in bash.   
> Also the bash behavior here is what matches /bin/[ most closely.
> 
> $ /bin/sh
> $ if [ $UID -ne 0 ] ; then
>  > echo not root
>  > fi
> [: -ne: unexpected operator
> $ exit
> $ echo $SHELL
> /usr/local/bin/bash
> [jeffrey@dobby ~/src/mount-rsnap]$ if [ $UID -ne 0 ] ; then
>  > echo not root
>  > fi
> not root
> 
> Does anyone have a recommendation of how to run this simple test in / 
> bin/sh 

if [ $(id -u) -ne 0 ]; then ...

As to why your test isn't working as expected, rewrite your script to
read:

#!/bin/sh
echo $UID

and you'll discover that UID is a bash environmental variable.

> and how to write tests reasonably portably?

That's a different question, and merits a much longer discussion
probably better had elsewhere.  I'd suggest comp.unix.shell.

-- 
George