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Re: RAR under linux: any alternative?



On Mon, 2005-12-12 at 22:49 -0800, Steve Lamb wrote:
--snip--
>     Yes, Alex, and you're showing your ignorance again.

Steve, I would appreciate it if you would refrain from referring to me
explicitly by name. Establishing a false sense of familiarity,
particularly in a discussion which is showing dangerous signs of being
heated, is not an exercise that I would like to participate in.

My discussions with you are about RAR, tar, and friends, not about you,
me, or any other personal matter.

--snip--
> from tar + gz.  Futhermore tar + gz + split does not even remotely begin to
> approach a multi-volume rar.  If you don't believe me, read the following and
> try...  *try* to understand...  My comments prefaced with "---"

Ok, I'll try, and I'll include my alternative, using nothing more than
tar, gz, and split (and md5sum as you did).

> --- I've created a multivolume rar set of some pictures.  The file,
> Lflying.jpg exists in one and only one volume.  I do an md5sum of the original
> file for comparison.
> 
> {grey@mania:~/t/t} md5sum ../Lflying.jpg
> 050f14ee2bacf23aa571a81c336ba4e5  ../Lflying.jpg

Ok. Same scenario, only using tar, split, and gzip. 

demonbane@Thief:~/gzip-proof$ md5sum Image08.png
324b47a61576cab05f12199457e953c3  Image08.png

> --- Delete all other volumes but the one that it exists in.
> 
> {grey@mania:~/t/t} rm test.part[12356].rar

demonbane@Thief:~/gzip-proof$ rm xa[ac-z].gz *.png

(I didn't use a separate directory, so deleting the original images here
as well.)

> --- List the volume to show you the file is there.  This is the first thing a
> split tar.gz cannot do.
> 
> {grey@mania:~/t/t} rar l test.part4.rar
> 
> RAR 3.30    Copyright (c) 1993-2004 Eugene Roshal    22 Jan 2004
> Shareware version         Type RAR -? for help
> 
> Volume test.part4.rar
> 
>  Name             Size   Packed Ratio  Date   Time     Attr      CRC   Meth Ver
> -------------------------------------------------------------------------------
>  Ascendance_tabard.png   145615    18247  <-- 20-09-05 23:50 -rw-r--r--
> E9E546BC m3c 2.9
>  Lflying.jpg     49115    48521  98% 15-04-05 23:29 -rwxr--r-- C0111A15 m3c 2.9
>  rava_face.png   162619    14973  --> 15-04-05 23:29 -rwxr--r-- 3301E1E0 m3c
> 2.9-------------------------------------------------------------------------------
>     2           211734    81741  38%

The output isn't quite as pretty as yours, but functionally essentially
the same.

demonbane@Thief:~/gzip-proof$ tar tvzf xab.gz
tar: This does not look like a tar archive
tar: Skipping to next header
-rw-r--r-- demonbane/demonbane 1005923 2005-12-13 00:14:55 Image08.png
-rw-r--r-- demonbane/demonbane 1164730 2005-12-13 00:14:55 Image12.png
tar: Unexpected EOF in archive
tar: Error is not recoverable: exiting now

> --- Note the CRC right there in the volume.  Gee, no need for my external
> md5sum except for this exercise.  Now to extract the file.
--- unless the part of the archive that gets corrupted is the CRC, with
the rest of the data intact

> {grey@mania:~/t/t} rar x test.part4.rar Lflying.jpg
> 
> RAR 3.30    Copyright (c) 1993-2004 Eugene Roshal    22 Jan 2004
> Shareware version         Type RAR -? for help
> 
> 
> Extracting from test.part4.rar
> 
> Extracting  Lflying.jpg                                               OK
> All OK

Ok, still following you here.

demonbane@Thief:~/gzip-proof$ tar xvvzf xab.gz
tar: This does not look like a tar archive
tar: Skipping to next header
-rw-r--r-- demonbane/demonbane 1005923 2005-12-13 00:14:55 Image08.png
-rw-r--r-- demonbane/demonbane 1164730 2005-12-13 00:14:55 Image12.png
tar: Unexpected EOF in archive
tar: Unexpected EOF in archive
tar: Error is not recoverable: exiting now

I don't get the pretty "All OK" message... darn. :(

> --- md5sum again to prove this file is the same as the above file.
> 
> {grey@mania:~/t/t} md5sum Lflying.jpg
> 050f14ee2bacf23aa571a81c336ba4e5  Lflying.jpg

demonbane@Thief:~/gzip-proof$ md5sum Image08.png
324b47a61576cab05f12199457e953c3  Image08.png

> --- And for comparison, here's the previons md5sum
> 
> 050f14ee2bacf23aa571a81c336ba4e5  ../Lflying.jpg

And for comparison, my previous md5sum. Your point being?

324b47a61576cab05f12199457e953c3  Image08.png

In the interests of full disclosure, this was not done in exactly the
manner that you would normally create a tar.gz. The tarring, and the
gzipping were done in reverse order. A quick command-line run-down of
the process:

tar cf - *.png | split -b 1m
for i in xa*; do gzip $i; done
rm *.png xa[ac-z].gz
tar xzf xab.gz


>     So, you show me tar.gz being able to extract a file from the middle of a
> split archive when none of the other volumes *even exist* and you'll have one
> leg to stand on about what is my opinion vs. what is *fact*.

So what exactly do I have to do to get the other leg then? :)

--snip--
>     I rest my case on your opinion versus my facts.

As do I.

> > My question,
> > as before, remains what practical benefit this software presents that
> > CANNOT be achieved otherwise?
> 
>     See above.  Tired of educating you Alex.  Really tired.

I am feeling pretty tired myself. But, then, it's past midnight, local
time. :)

As a side note, I'm all for continuing this discussion in a civil manner
(if there is anything left to discuss that is), but I don't feel that
it's appropriate for either of us to make personal assaults against the
other in the course of said discussion.

If I have done that in any of my previous statements in this message, or
any other one, I do apologize. So shall we move on?

My question still stands; what practical benefit does the proprietary
RAR solution present that CANNOT be achieved by using the free tools of
tar, gz, and split?

-- 
Alex Malinovich
Support Free Software, delete your Windows partition TODAY!
Encrypted mail preferred. You can get my public key from any of the
pgp.net keyservers. Key ID: A6D24837

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