From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 23980 invoked from network); 9 Dec 2020 04:36:19 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 9 Dec 2020 04:36:19 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id DA57D94547; Wed, 9 Dec 2020 14:36:16 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 8D71F944D4; Wed, 9 Dec 2020 14:35:45 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=pass (2048-bit key; unprotected) header.d=dartmouth.edu header.i=@dartmouth.edu header.b="TX+wBjN3"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id E9A28944D4; Wed, 9 Dec 2020 14:35:41 +1000 (AEST) Received: from mail-qt1-f173.google.com (mail-qt1-f173.google.com [209.85.160.173]) by minnie.tuhs.org (Postfix) with ESMTPS id E612B944D3 for ; Wed, 9 Dec 2020 14:35:40 +1000 (AEST) Received: by mail-qt1-f173.google.com with SMTP id j26so15279qtq.8 for ; Tue, 08 Dec 2020 20:35:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dartmouth.edu; s=google1; h=mime-version:from:date:message-id:subject:to; bh=MEYyowo7aHh7o1viZuWto37y5JUc+Q8fe6HC7fpmBwA=; b=TX+wBjN3v6P4SlHuEC9A/UA9ZTbV2uxNGUKWJN6E5QDOAe6TthIhFF1+93+LtXZ8Ri l5+b3GnKGHHwr6TbR1nIp+XAiWAS35+A4BEbK56+Hwx7M7pDKAR5UHgqHJl15zuMx8sL 0BYyhPJvJHugFxewWo94Duy2zrLyFT+Mdw/sOEoU3qJYNaEcImkZUMm6kmmuYtxaxV8j FqQbPiv1+dT8fY4iFA0Hr3op9VAw3F/wqOsB7LnPwjs+mqGSkMAWo5jr4J6e0avyBOVv E/6yRqohUHTUbhasIngPPv2m+YjdHC54/EYHWe9y4MUL/hJ2Co2p0bVDoNYYBeChUdZ+ Z0Mw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=MEYyowo7aHh7o1viZuWto37y5JUc+Q8fe6HC7fpmBwA=; b=j5ZPF8fLDZy92LeQlNoSQtOcVTwCdNuBhQyV+D375HfpiWTw3TA9WEP0V8YEV3lP4S x/u1DMwerlbdFXh9+nwePKSdV5T1EkDgej1V9ohpf/yZiBao3SgnLL9D3VhXfOWY2JQp Mo1MAKvMoaDON9CzOGKl9YZOeGRafa0JJP/9L7qyPUp9IRAwcD3RDSdM12HTFxOp/UHL xFgvW1aCQy1aw1wnT2EPZ3MVAESmtJd5P5VK+RSnIIVvlpZS3uXbn2lG1iTi0fVQktNl 2vWb2sJe0SATZkwhs/LDNBZQR0d9i2AsiYxkzRVKSvxuPdemJn35KuhWmLpqh008GuZQ v7UQ== X-Gm-Message-State: AOAM531a/XrijaeDe0BF2uYYYHXu39IO/DTcCkSy/1OvE2pB3I+kxSBs +uiVzCD30YWxxFS7QHCfcIR9fLqxNyO+jngCP81+ipwlq0jUgQ== X-Google-Smtp-Source: ABdhPJyNFDHFZWhP6fS+oBNq1vJ8EOek1D4CC1HyoZwi8l6h+gp7cDzfNhHy3qnbbeKYBHvTcZ7n03/m5zpajxqO8vU= X-Received: by 2002:ac8:5ccd:: with SMTP id s13mr1046134qta.87.1607488538342; Tue, 08 Dec 2020 20:35:38 -0800 (PST) MIME-Version: 1.0 From: M Douglas McIlroy Date: Tue, 8 Dec 2020 23:35:24 -0500 Message-ID: To: tuhs@tuhs.org Content-Type: text/plain; charset="UTF-8" Subject: [TUHS] Were cron and at done at the same time? Or one before the other? X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" This pair of commands exemplifies a weakness in the way Unix evolved. Although it was the product of a shared vision, It was not a product-oriented project. Unix commands work well together, but they don't necessarily work alike. It would be nice if identifiable families of commands had similar user interfaces. However, cron and at were written by different individuals, apparently with somewhat different tastes. Unix folks were close colleagues, but had no organized design committee. Time specs in cron and at are markedly different. A more consequential example is data-field specs (or lack thereof) in sort, join, cut, comm and uniq. The various specs were recognized as "wildly incongruent" in a BUG remak. However there was no impetus for unification. To paraphrase John Cocke (speaking about Fortran): one must understand that Unix commands are not a logical language. They are a natural language--in the sense that they developed by organic evolution, not "intelligent design". Doug