From owner-freebsd-questions@freebsd.org Mon Sep 21 08:09:49 2020 Return-Path: Delivered-To: freebsd-questions@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 904F63E9BF0 for ; Mon, 21 Sep 2020 08:09:49 +0000 (UTC) (envelope-from 4250.82.1d4c50000597a92.cd180d80f8a7d32198de8b342bc83d36@email-od.com) Received: from s1-b0c6.socketlabs.email-od.com (s1-b0c6.socketlabs.email-od.com [142.0.176.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4Bvxtg6tfyz3dwd for ; Mon, 21 Sep 2020 08:09:47 +0000 (UTC) (envelope-from 4250.82.1d4c50000597a92.cd180d80f8a7d32198de8b342bc83d36@email-od.com) DKIM-Signature: v=1; a=rsa-sha256; d=email-od.com;i=@email-od.com;s=dkim; c=relaxed/relaxed; q=dns/txt; t=1600675788; x=1603267788; h=content-transfer-encoding:content-type:mime-version:references:in-reply-to:message-id:subject:to:from:date:x-thread-info; bh=LDZFFKPso3yTZVXJyb6t6jIIBtxUcVRf4MO5isLiaCg=; b=EWrXnzXotqiUOx2qyb1kmCxf60+j3OfEa0h/QAfUCzn7kheWShuMr+Uvrnk25Mvt18oy0mvnFlbwvDtXaiZ5iMVPNKvkGlspQ2NT/UWVEFf1zqYCWKwvAfce3HvNO5cKEORZbrKCPfGfhwG7u3EwNqeL5FpkqN71dCkhVyhpKSE= X-Thread-Info: NDI1MC45Mi4xZDRjNTAwMDA1OTdhOTIuZnJlZWJzZC1xdWVzdGlvbnM9ZnJlZWJzZC5vcmc= Received: from r1.us-east-2.aws.in.socketlabs.com (r1.us-east-2.aws.in.socketlabs.com [142.0.189.1]) by mxsg2.email-od.com with ESMTP(version=Tls12 cipher=Aes256 bits=256); Mon, 21 Sep 2020 04:09:39 -0400 Received: from smtp.lan.sohara.org (EMTPY [185.202.17.215]) by r1.us-east-2.aws.in.socketlabs.com with ESMTP(version=Tls12 cipher=Aes256 bits=256); Mon, 21 Sep 2020 04:09:39 -0400 Received: from [192.168.63.1] (helo=steve.lan.sohara.org) by smtp.lan.sohara.org with smtp (Exim 4.94 (FreeBSD)) (envelope-from ) id 1kKGtF-000N3n-Fi for freebsd-questions@freebsd.org; Mon, 21 Sep 2020 09:09:37 +0100 Date: Mon, 21 Sep 2020 09:09:37 +0100 From: Steve O'Hara-Smith To: freebsd-questions@freebsd.org Subject: Re: Error message output Message-Id: <20200921090937.fc1fbed5bdcd9615d77ea8f4@sohara.org> In-Reply-To: <528b2c90-18c4-9e95-a150-67344154c66c@holgerdanske.com> References: <20200920191108.22864e5c.freebsd@edvax.de> <528b2c90-18c4-9e95-a150-67344154c66c@holgerdanske.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; amd64-portbld-freebsd12.0) X-Clacks-Overhead: "GNU Terry Pratchett" Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 4Bvxtg6tfyz3dwd X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=email-od.com header.s=dkim header.b=EWrXnzXo; dmarc=none; spf=pass (mx1.freebsd.org: domain of 4250.82.1d4c50000597a92.cd180d80f8a7d32198de8b342bc83d36@email-od.com designates 142.0.176.198 as permitted sender) smtp.mailfrom=4250.82.1d4c50000597a92.cd180d80f8a7d32198de8b342bc83d36@email-od.com X-Spamd-Result: default: False [-2.92 / 15.00]; MID_RHS_MATCH_FROM(0.00)[]; ARC_NA(0.00)[]; R_DKIM_ALLOW(-0.20)[email-od.com:s=dkim]; NEURAL_HAM_MEDIUM(-1.04)[-1.038]; FROM_HAS_DN(0.00)[]; RWL_MAILSPIKE_GOOD(0.00)[142.0.176.198:from]; MV_CASE(0.50)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; TO_DN_NONE(0.00)[]; DMARC_NA(0.00)[sohara.org]; RCPT_COUNT_ONE(0.00)[1]; NEURAL_HAM_LONG(-1.00)[-0.999]; RCVD_COUNT_THREE(0.00)[4]; R_SPF_ALLOW(-0.20)[+ip4:142.0.176.0/20]; DKIM_TRACE(0.00)[email-od.com:+]; NEURAL_HAM_SHORT(-1.18)[-1.181]; RCVD_IN_DNSWL_NONE(0.00)[142.0.176.198:from]; FORGED_SENDER(0.30)[steve@sohara.org,4250.82.1d4c50000597a92.cd180d80f8a7d32198de8b342bc83d36@email-od.com]; MIME_TRACE(0.00)[0:+]; RCVD_TLS_LAST(0.00)[]; ASN(0.00)[asn:7381, ipnet:142.0.176.0/22, country:US]; FROM_NEQ_ENVFROM(0.00)[steve@sohara.org,4250.82.1d4c50000597a92.cd180d80f8a7d32198de8b342bc83d36@email-od.com]; MAILMAN_DEST(0.00)[freebsd-questions] X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 21 Sep 2020 08:09:49 -0000 On Sun, 20 Sep 2020 22:12:24 -0700 David Christensen wrote: > I have been migrating my programming style towards a data flow paradigm, > which includes "command-line filters". So, an "ideal" command-line > program or script would: > > * Use stdin for the input data. > > * Use stdout for the output data. > > * Use configuration files, command-line options and arguments, received > signals and direct tty reads for out-of-band/ non-data input. This is where the standard set of unix devices is lacking, I have long thought that there should be a stdctl then stdin/stdout are data flow and stdtctl/stderr are control flow. > * Use stderr, log files, and the exit value for out-of-band/ non-data > output. -- Steve O'Hara-Smith