From owner-freebsd-hackers@FreeBSD.ORG  Sun Oct 10 05:31:21 2010
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 804491065673
	for <freebsd-hackers@freebsd.org>; Sun, 10 Oct 2010 05:31:21 +0000 (UTC)
	(envelope-from julian@freebsd.org)
Received: from out-0.mx.aerioconnect.net (outp.internet-mail-service.net
	[216.240.47.239])
	by mx1.freebsd.org (Postfix) with ESMTP id 5C5E68FC18
	for <freebsd-hackers@freebsd.org>; Sun, 10 Oct 2010 05:31:21 +0000 (UTC)
Received: from idiom.com (postfix@mx0.idiom.com [216.240.32.160])
	by out-0.mx.aerioconnect.net (8.13.8/8.13.8) with ESMTP id
	o9A5VKlJ014740; Sat, 9 Oct 2010 22:31:20 -0700
X-Client-Authorized: MaGic Cook1e
X-Client-Authorized: MaGic Cook1e
X-Client-Authorized: MaGic Cook1e
X-Client-Authorized: MaGic Cook1e
Received: from julian-mac.elischer.org
	(h-67-100-89-137.snfccasy.static.covad.net [67.100.89.137])
	by idiom.com (Postfix) with ESMTP id 804CA2D6015;
	Sat,  9 Oct 2010 22:31:19 -0700 (PDT)
Message-ID: <4CB14FD5.9090505@freebsd.org>
Date: Sat, 09 Oct 2010 22:32:05 -0700
From: Julian Elischer <julian@freebsd.org>
User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.4; en-US;
	rv:1.9.2.9) Gecko/20100915 Thunderbird/3.1.4
MIME-Version: 1.0
To: Garrett Cooper <gcooper@freebsd.org>
References: <1286397912.27308.40.camel@localhost.localdomain>	<AANLkTikoohMo5ng-RM3tctTH__P6cqhQpm=FPhSE9mMg@mail.gmail.com>	<51B4504F-5AA4-47C5-BF23-FA51DE5BC8C8@vicor.com>	<AANLkTim=BLkd229vdEst8U0ugpq3UsHPxjZZp2qaJxH-@mail.gmail.com>	<238E0B24-AA12-4684-9651-84DA665BE893@vicor.com>
	<AANLkTinCxd9aDbr7GifEdeOpdcW4d+4ZcQWF0TK_mC=8@mail.gmail.com>
In-Reply-To: <AANLkTinCxd9aDbr7GifEdeOpdcW4d+4ZcQWF0TK_mC=8@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
X-Scanned-By: MIMEDefang 2.67 on 216.240.47.51
Cc: Brandon Gooch <jamesbrandongooch@gmail.com>, freebsd-hackers@freebsd.org,
	Devin Teske <dteske@vicor.com>
Subject: Re: sysrc -- a sysctl(8)-like utility for managing /etc/rc.conf et.
 al.
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sun, 10 Oct 2010 05:31:21 -0000

  On 10/9/10 7:30 PM, Garrett Cooper wrote:
>
>> [ "..." ] is the same thing as [ -n "..." ] or test -n "..."
>> [ ! "..." ] is the same things as [ -z "..." ] or test -z "..."
>> I'll never understand why people have to throw an extra letter in there and
>> then compare it to that letter.
> I ran into issues using ! on Solaris ksh recently (not using test),
> and I agree that your example below is more straightforward and
> readable than the other examples I've dealt with in the past.


Ah that reminds me for the reason for "X$foo" = "X"

it's in case $foo evaluates to "-n" or similar...

It's been a long time... but these days a data misevaluation leads to 
such things ad  SQL injection attacks
and I see no reason that a shell injection attack shouldn't be possible.