cpio, tar, dump ramblings Re: [LUG] something to do with someone explaining how to compile, butwhy?

[Simon Waters <Simon@xxxxxxxxxxxxxxxxxxxx>]

Bill Wilson wrote:
> Let me introduce you to the pleasures of cpio rather than tame tar.
> This one is just for you for christmas  cpio -itcvudB < /dev/rStp0

cpio --extract --list -H newc --verbose --unconditional
--make-directories --block-size=5120

Hmm I thought the "c" and the "B" are superfluous as format and
block size should be autodetected on input with GNU cpio and
modern (well SCSI and SCSI like) tape drives, similarly "u" and
"d" don't impact "t" afaik. 

Non-GNU cpio's may be less friendly, but then this is one area
where you have long got less for your money, when buying
proprietary (well you usually got AT&T more, not GNU less, but
you know what I mean ;-).

So that reduces to "cpio --extract --list --verbose" (or "cpio
-itv") which is almost comprehensible", of course "GNU tar"
understands that listing files in an archive implies that you
read the archive (or "tar -tv"), and doesn't need to be told
that by the user, I guess a concession required for backward
compatibility.

I think people tend to learn cpio command strings by rote,
without thinking, as the consequences of thinking and getting it
wrong are so catastrophic when system backups are involved.

GNU tar on the other hand has sane defaults, and a "cd / ; tar
cvf /dev/rmt/0m ." has a reasonable chance of storing enough to
rebuild a working system.

Of course "dump" was the best Unix backup tool (except for SCO
who did hideous things in Unixware), and is far better suited to
purpose than some very expensive programs that can do a lot
more, although I despair at the need to specify blocksize and
related information in the AT&T implementation - why not put out
a big sign "welcome to the 1970's" ;-)

Still I think we owe it to those that come after us to use the
newer longer descriptive option names on commands when scripting
(especially backup scripts!) - says the man who still thinks of
Unix file permissions in octal.

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