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From: mwm@eris.UUCP
Newsgroups: comp.sys.amiga
Subject: Re: Cp: A replacement for AmigaDos Copy
Message-ID: <3718@jade.BERKELEY.EDU>
Date: Tue, 26-May-87 00:16:16 EDT
Article-I.D.: jade.3718
Posted: Tue May 26 00:16:16 1987
Date-Received: Wed, 27-May-87 01:49:47 EDT
References: <741@van-bc.UUCP> <121@gtss.UUCP> <7180@amdahl.amdahl.com>
Sender: usenet@jade.BERKELEY.EDU
Reply-To: mwm@eris.BERKELEY.EDU (Mike (My watch has windows) Meyer)
Organization: Missionaria Phonibalonica
Lines: 86
Keywords: AmigaDos Copy Regular Expressions

In article <7180@amdahl.amdahl.com> kim@amdahl.amdahl.com (Kim DeVaughn) writes:
<In article <121@gtss.UUCP>, chas@gtss.UUCP (Charles Cleveland) writes:
<> In article <741@van-bc.UUCP> jlydiatt@van-bc.UUCP (Jeff Lydiatt) writes:
<> >It ... has the added bonus that it retains the date of copied file.
<>
<> This is not a feature, it is a bug :-).
<
<Well, this is probably one of those "religious issues", but I *strongly*
<disagree with you, Charles!

No, it's not a religious issue. It depends on what you're using copy for.

<Without such date retention, it can become quite difficult to figure-out just
<which "incarnation" of a set of files (i.e., directory of files) is really the
<oldest, newest, etc.  And of course, many processing programs (such as "make",
<and various archiving/backup programs) rely on the modification date to guide
<their processing.

Odd, I never run into that problem. Maybe because my habits come from
large systems instead of floppy-based systems? Or maybe it's because I
make backups with backup utilities, and use copy for making copies.

<It may interest you to know that the MS-DOS and PC-DOS "copy" command retains
<the file date

Given the general quality of software sold by IBM and Microsoft, this
strikes me as a good indication that copy preserving the date is
wrong 1/2-).

<many UNIX(R) utilities go to the trouble of preserving/restoring it
<(e.g., tar, pack, compress, etc.), as do archivers like ARC, PKARC,
<etc.

Ah, but those unix utilities create archives or backups, *not* copies.
There jobs is to make it possible to recreate files exactly, which
includes the create/modification/access times.

On the other hand, Unix cp creates copies. It makes the creation and
modification date the current time (didn't check access time, but it
hardly matters for this).

<Maybe I'm overlooking something obvious, but I sure can't come up with the
<"good reason" you alluded to for not retaining the date on a pure copy
<operation.

You want a good reason for copy (especially "copy all") to preserve
dates? How about because after I copy new software from a floppy to my
hard disk, I'd like the next incremental backup to pick up all the new
stuff. That way, I don't have to rebuild my hard disk from umpteen
Fish disks (or whatever).

Or how about the following (which I do):

	copy ttyio.c ttyio.c.save
	emacs ttyio.c			; want to try out some new changes...
	make
	mg				; see how they work
	copy ttyio.c.save ttyio.c	; they don't
	make				; gee, nothing happens...

Since copy put the wrong date on the new copy of ttyio.c, it wound up
as "older" than ttyio.o. Similarly, if I get a new version of mg, and
just want to try the ttyio.c, if it was actually edited before I last
tweaked mine, the make won't find anything to do.

<If you *do* want the file to have the current date, there is is
<always "touch" ... :-)!

And if you want the date preserved, there's always "setdate".

In summary, if you want a command to make backups of a file for you, I
suggest you use a backup utility. Don't try and pervert copy into such
a utility. I want copy to make new copies of a file for me.

<Anyway, thanks to Jeff for posting the new copy, with file-dating working
<the way it should have in the first place!

Gee, I must have missed that posting. All I've got is one where
file-dating is broken :-).

	<mike
--
How many times do you have to fall			Mike Meyer
While people stand there gawking?			mwm@berkeley.edu
How many times do you have to fall			ucbvax!mwm
Before you end up walking?				mwm@ucbjade.BITNET