From owner-freebsd-questions Thu Jun 25 07:11:24 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id HAA13380 for freebsd-questions-outgoing; Thu, 25 Jun 1998 07:11:24 -0700 (PDT) (envelope-from owner-freebsd-questions@FreeBSD.ORG) Received: from dan.emsphone.com (dan@dan.emsphone.com [199.67.51.101]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id HAA13328 for ; Thu, 25 Jun 1998 07:10:51 -0700 (PDT) (envelope-from dan@dan.emsphone.com) Received: (from dan@localhost) by dan.emsphone.com (8.8.8/8.8.8) id JAA29631; Thu, 25 Jun 1998 09:10:11 -0500 (CDT) (envelope-from dan) Message-ID: <19980625091010.A29583@emsphone.com> Date: Thu, 25 Jun 1998 09:10:10 -0500 From: Dan Nelson To: Doug White , Sue Blake Cc: RPD , freebsd-questions@FreeBSD.ORG Subject: Re: copying/duplicating disks: replacing IDE with scsi References: <19980625133521.29606@welearn.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.92.8i In-Reply-To: ; from "Doug White" on Wed Jun 24 22:47:54 GMT 1998 X-OS: FreeBSD 2.2.6-STABLE Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In the last episode (Jun 24), Doug White said: > On Thu, 25 Jun 1998, Sue Blake wrote: > > > > -R is recursively copy, -p is preserve permissions. > > > > So why is copying sometimes done with tar instead of cp? > > Tar remembers to preserve permissions, and cp won't unless you run it > -with Rp. Well, to be nitpicky, tar won't remember either, unless you add a 'p' to the extract command. But by far the biggest reason to copy with a tar|tar pipeline is the overlapping I/O. While the first tar is reading, the last tar is writing. A plain "cp -pR" can only be reading or writing at any one time. -Dan Nelson dnelson@emsphone.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message