From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from minnie.tuhs.org (minnie.tuhs.org [45.79.103.53]) by inbox.vuxu.org (OpenSMTPD) with ESMTP id a803e9d5 for ; Thu, 5 Mar 2020 04:57:47 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id 88EC49D73F; Thu, 5 Mar 2020 14:57:44 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 5363B9D71C; Thu, 5 Mar 2020 14:57:26 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id 4F1C09D71C; Thu, 5 Mar 2020 14:57:23 +1000 (AEST) Received: from mail.cs.dartmouth.edu (mail.cs.dartmouth.edu [129.170.212.100]) by minnie.tuhs.org (Postfix) with ESMTPS id 4006D9D71B for ; Thu, 5 Mar 2020 14:57:22 +1000 (AEST) Received: from tahoe.cs.Dartmouth.EDU (tahoe.cs.dartmouth.edu [129.170.212.20]) by mail.cs.dartmouth.edu (8.15.2/8.15.2) with ESMTPS id 0254vKAO1325812 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO) for ; Wed, 4 Mar 2020 23:57:20 -0500 Received: from tahoe.cs.Dartmouth.EDU (localhost.localdomain [127.0.0.1]) by tahoe.cs.Dartmouth.EDU (8.15.2/8.14.3) with ESMTP id 0254vKkK142486 for ; Wed, 4 Mar 2020 23:57:20 -0500 Received: (from doug@localhost) by tahoe.cs.Dartmouth.EDU (8.15.2/8.15.2/Submit) id 0254vJ2Y142485 for tuhs@tuhs.org; Wed, 4 Mar 2020 23:57:19 -0500 From: Doug McIlroy Message-Id: <202003050457.0254vJ2Y142485@tahoe.cs.Dartmouth.EDU> Date: Wed, 04 Mar 2020 23:57:19 -0500 To: tuhs@tuhs.org User-Agent: Heirloom mailx 12.5 7/5/10 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Subject: Re: [TUHS] Command line options and complexity 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" > These go all the way back to v7 unix, where ls has an option to reverse the sort order (which could have been done by passing the output to tac). A cool idea, but tac was not in v7. And tail didn't get the -r option until v8. As for rev, I don't know why it was first written, but one use was to examine suffixes--a kind of thing that several word lovers in the Unix lab were prone to do. Apropos of using rev to make rhyming dictionaries, Walker's Rhyming Dictionary was published decades before Noah Webster's dictionary appeared and stayed in print for about 200 years. Notionally the relation between webster and walker is rev walker Doug