From owner-freebsd-questions@freebsd.org Wed Feb 1 19:59:39 2017 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 26F12CCCE83 for ; Wed, 1 Feb 2017 19:59:39 +0000 (UTC) (envelope-from byrnejb@harte-lyne.ca) Received: from inet08.hamilton.harte-lyne.ca (inet08.hamilton.harte-lyne.ca [216.185.71.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "inet08.hamilton.harte-lyne.ca", Issuer "CA_HLL_ISSUER_2016" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id EC25C1398 for ; Wed, 1 Feb 2017 19:59:38 +0000 (UTC) (envelope-from byrnejb@harte-lyne.ca) Received: from localhost (localhost [127.0.0.1]) by inet08.hamilton.harte-lyne.ca (Postfix) with ESMTP id 3A31862324; Wed, 1 Feb 2017 14:59:31 -0500 (EST) X-Virus-Scanned: amavisd-new at harte-lyne.ca Received: from inet08.hamilton.harte-lyne.ca ([127.0.0.1]) by localhost (inet08.hamilton.harte-lyne.ca [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id YKZlT_sfEXya; Wed, 1 Feb 2017 14:59:29 -0500 (EST) Received: from webmail.harte-lyne.ca (inet04.hamilton.harte-lyne.ca [216.185.71.24]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by inet08.hamilton.harte-lyne.ca (Postfix) with ESMTPSA id C2A686231B; Wed, 1 Feb 2017 14:59:28 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=harte-lyne.ca; s=dkim_hll; t=1485979169; bh=OAxeDsA8Fxv6t7c45GisVgNsrmOwpIRkBXUjhi+7YHE=; h=In-Reply-To:References:Date:Subject:From:To:Cc:Reply-To; b=OsUbMuJtV/1IkFHe8fJFkF1rGENrYIykCNl438pazyk7xnBpxpLdp+cWEQC8wWUyN MBfYNOS1DAlMxEgBpyM4ZymFJ06dxAyBnBiRTeCpvR+QilFFCTUo7aj8Rvij5pUvNv NhlEOR2EyBA1O+oK6irqV3N1zutteFPaIk9CuEa2rvXFtalQJ8pPEz4O5YJeBTlzFw YuPs5FfOuoQo1EJ9AzIW/Zd7MZX6hJ2eu1sF/8fGbQXqCJXrXEy8sijNnUea0o3Fn4 svYMJPaNn5MRqh6J8lREGyGGDaIzeVHHwwzJ1oUElhNF5JEqEmmw+1eeI0yxoi11vC ZJhZab+ruG+fQ== Received: from 216.185.71.44 (SquirrelMail authenticated user byrnejb_hll) by webmail.harte-lyne.ca with HTTP; Wed, 1 Feb 2017 14:59:29 -0500 Message-ID: <84861d4906923faec222f96580833c2f.squirrel@webmail.harte-lyne.ca> In-Reply-To: <20170131200143.00c5e5da.freebsd@edvax.de> References: <20170131161824.a9f1ef46.freebsd@edvax.de> <20170131185103.7f911dfb.freebsd@edvax.de> <5f51e2c3bdb8a20c6a7786c2b345c957.squirrel@webmail.harte-lyne.ca> <20170131200143.00c5e5da.freebsd@edvax.de> Date: Wed, 1 Feb 2017 14:59:29 -0500 Subject: Re: Variable assignment in sh From: "James B. Byrne" To: "Polytropon" Cc: freebsd-questions@freebsd.org Reply-To: byrnejb@harte-lyne.ca User-Agent: SquirrelMail/1.4.22-4.el6 MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 01 Feb 2017 19:59:39 -0000 On Tue, January 31, 2017 14:01, Polytropon wrote: > On Tue, 31 Jan 2017 12:56:40 -0500, James B. Byrne wrote: >> How would bash become unavailable on this particular system without >> someone specifically removing it? > > A rare occassion, but possible. Let's say in a worst-case scenario, > /usr isn't mounted, and you need to stick with what's on /, then > bash, which per default is /usr/local/bin/bash, isn't available. > However, bash can be linked statically _and_ copied to a location > on /, then you won't have that kind of problem. > > Portability also could be a problem when you try to run something > that expects bash on a system where bash isn't installed. Always > keep in mind that bash is _not_ part of FreeBSD, while sh is. Yes, I will do that from here on. > > I know, those are very special cases, and if your goal is not > portability and "guaranteed availability", then it won't hit you. > I just thought it's worth being mentioned. Thank you. I have found your explanation of what goes on under the covers very interesting. In this case I am dealing with a zfs system so if /usr is not there then neither is /bin. -- *** e-Mail is NOT a SECURE channel *** Do NOT transmit sensitive data via e-Mail Do NOT open attachments nor follow links sent by e-Mail James B. Byrne mailto:ByrneJB@Harte-Lyne.ca Harte & Lyne Limited http://www.harte-lyne.ca 9 Brockley Drive vox: +1 905 561 1241 Hamilton, Ontario fax: +1 905 561 0757 Canada L8E 3C3