X-Recipient: archive-cygwin@delorie.com X-SWARE-Spam-Status: No, hits=-1.3 required=5.0 tests=AWL,BAYES_00,MISSING_HEADERS,SPF_HELO_PASS,SPF_PASS X-Spam-Check-By: sourceware.org Date: Thu, 29 Jan 2009 18:51:25 -0600 (CST) From: Tim McDaniel cc: cygwin@cygwin.com Subject: Re: Setting Integer Variables in Bash In-Reply-To: Message-ID: References: <21737864.post@talk.nabble.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-IsSubscribed: yes Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Delivered-To: mailing list cygwin@cygwin.com On Thu, 29 Jan 2009, Mark J. Reed wrote: > On Thu, Jan 29, 2009 at 5:54 PM, whitewall wrote: >> #! /cygdrive/c/cygwin/bin/bash >> declare -i Red >> declare -i Green >> Red=10 >> Green=$Red+1 > > Since you've declared both Green and Red as integer, you should just > do Green=Red+1, without the dollar sign. Doing Green=$Red+1 first > takes Red's value, which is stored as an integer, expands it back > into its decimal string representation, and then reparses it to > yield its integer value. There IS one subtle difference. If you're running with "set -x", Green=$Red+1 will echo + Green=10+1 But Green=Red+1 will echo + Green=Red+1 (assuming that you've not changed PS4, IFS, &c &c). You can decide which "set -x" output you like. I found that I preferred the substituted forms, the ones with $this and $that. -- Tim McDaniel, tmcd@panix.com -- 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/