From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <zsh-users-return-17404-mason-zsh=primenet.com.au@zsh.org>
Received: (qmail 28813 invoked by alias); 17 Nov 2012 21:57:36 -0000
Mailing-List: contact zsh-users-help@zsh.org; run by ezmlm
Precedence: bulk
X-No-Archive: yes
List-Id: Zsh Users List <zsh-users.zsh.org>
List-Post: <mailto:zsh-users@zsh.org>
List-Help: <mailto:zsh-users-help@zsh.org>
X-Seq: 17404
Received: (qmail 12611 invoked from network); 17 Nov 2012 21:57:34 -0000
X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on f.primenet.com.au
X-Spam-Level: 
X-Spam-Status: No, score=-1.8 required=5.0 tests=BAYES_00,DKIM_SIGNED,
	T_DKIM_INVALID autolearn=no version=3.3.2
Received-SPF: none (ns1.primenet.com.au: domain at bunkus.org does not designate permitted sender hosts)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=bunkus.org;
	s=mail201203; t=1353188939;
	bh=+r09fDbwoMef+1rrvgOfpdql8KgftMfxJv/fKkT5xCY=;
	h=MIME-Version:In-Reply-To:References:Date:Message-ID:Subject:From:
	 To:Cc:Content-Type;
	b=AdjJZm9SE9+xoqmpp8EUhaWd0PmaKFrNZ2JXCXaisL8vpChaeMCA+KqqN8iMvmaeK
	 lCB/SWQaK+2+JX6D2uAo4btr4X9N8Ffx7Ra+s0zAcm6S+N6jPtwG8vfvcapY6uEtpT
	 AsWrLIy5PbbW3DRQHHDiDssNT6Vkekr61dXSRsB4=
MIME-Version: 1.0
In-Reply-To: <50A7FD3C.9070306@eastlink.ca>
References: <50A7FD3C.9070306@eastlink.ca>
Date: Sat, 17 Nov 2012 22:48:56 +0100
Message-ID: <CANPayMQK+nYt2aUCrYF1ePUq0HDmByT3kAS7UXtE-ZutxyLJnw@mail.gmail.com>
Subject: Re: ${var: -1:1} vs. ${var:-1:1}
From: Moritz Bunkus <moritz@bunkus.org>
To: Ray Andrews <rayandrews@eastlink.ca>
Cc: zsh-users@zsh.org
Content-Type: text/plain; charset=UTF-8

Hey,

if you don't put a space there then the parser thinks that this the
"${variable:-default} syntax which means "expands to the variable's
content if the variable is set and to 'default' if it is unset". Can
be seen easily with:

[0 mosu@sweet-chili ~] echo ${thisvarisnotset:-1:1}
1:1

So the '1:1' is interpreted as the 'default'. You probably never saw
that result because you were trying to extract the last character from
a string, meaning you always used a variable that was set.

Kind regards,
mosu