From owner-freebsd-questions@FreeBSD.ORG  Mon Jan 12 03:07:21 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 EBA1B1065672
	for <freebsd-questions@freebsd.org>;
	Mon, 12 Jan 2009 03:07:21 +0000 (UTC)
	(envelope-from dan@dan.emsphone.com)
Received: from email1.allantgroup.com (email1.emsphone.com [199.67.51.115])
	by mx1.freebsd.org (Postfix) with ESMTP id 953578FC0A
	for <freebsd-questions@freebsd.org>;
	Mon, 12 Jan 2009 03:07:21 +0000 (UTC)
	(envelope-from dan@dan.emsphone.com)
Received: from dan.emsphone.com (dan-a.emsphone.com [199.67.51.107])
	by email1.allantgroup.com (8.14.0/8.14.0) with ESMTP id n0C37InF063618
	(version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO)
	for <freebsd-questions@freebsd.org>;
	Sun, 11 Jan 2009 21:07:19 -0600 (CST)
	(envelope-from dan@dan.emsphone.com)
Received: from dan.emsphone.com (smmsp@localhost [127.0.0.1])
	by dan.emsphone.com (8.14.3/8.14.3) with ESMTP id n0C37Ipt016841
	(version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO)
	for <freebsd-questions@freebsd.org>;
	Sun, 11 Jan 2009 21:07:18 -0600 (CST)
	(envelope-from dan@dan.emsphone.com)
Received: (from dan@localhost)
	by dan.emsphone.com (8.14.3/8.14.3/Submit) id n0C37HUX016806;
	Sun, 11 Jan 2009 21:07:17 -0600 (CST) (envelope-from dan)
Date: Sun, 11 Jan 2009 21:07:17 -0600
From: Dan Nelson <dnelson@allantgroup.com>
To: Jeffrey Goldberg <jeffrey@goldmark.org>
Message-ID: <20090112030717.GA57874@dan.emsphone.com>
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>
X-OS: FreeBSD 7.1-STABLE
User-Agent: Mutt/1.5.18 (2008-05-17)
X-Virus-Scanned: ClamAV version 0.94.1,
	clamav-milter version 0.94.1 on email1.allantgroup.com
X-Virus-Status: Clean
X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-2.0.2
	(email1.allantgroup.com [199.67.51.78]);
	Sun, 11 Jan 2009 21:07:19 -0600 (CST)
X-Scanned-By: MIMEDefang 2.45
Cc: "mail.list freebsd-questions" <freebsd-questions@freebsd.org>
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 03:07:22 -0000

In the last episode (Jan 11), Jeffrey Goldberg said:
> 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 and how to write tests reasonably portably?

UID=$(id -u)
if [ $UID -ne 0 ] ; then
 echo not root
fi

UID is not a variable set by /bin/sh, which is why the test fails.

http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_05_03

-- 
	Dan Nelson
	dnelson@allantgroup.com