[Pan-users] Re: Pan-users Digest, Vol 20, Issue 15

[Duncan]

datasong posted <address@hidden>, excerpted below,  on
Wed, 28 Jul 2004 15:07:22 -0700:

> address@hidden wrote:
>> 
>> (Note that this only helps individual files appear as single posts: If you
>> are looking at huge files, like ISOs or large movies, the poster will
>> often split the compressed file into smaller files before posting
>> (something like .r01, .r02, etc.). Each of these smaller files will appear
>> as it's own Post in Pan's header pane.)
>> 
> When this is the case but the parts are posted like part01.rar, 
> part02.rar, part03.rar, etc. how does one get them recombined?

If they are RARs, Grahame answered.  If they are simply pieces of the
file, as I've seen MPEGs and the like posted occasionally, just save all
the parts to the same dir and use cat, redirecting output to a file, on
them.  Thus, assuming its a split mpeg with extensions of the form
.mpeg.### where the ### are digits, and that only the parts to that mpeg
are in that dir, a command such as the following will work:

cat *>test.mpeg

Some notes.

1) As long as the first part is there, a part or more can be missing and
the file still recombined, with some formats, such as mpeg.  There will
simply be a skip and a slight bit of static at the spot where the missing
file is located.  Of course, some other more compressed  formats won't
work quite as well, because they compress using a full anchor frame every
X frames, then only include the changes between each frame until the next
anchor frame.  This sort of format will have a longer period of static, as
some anchor frames will have been lost in the missing part, and the pickup
will then start updating an old anchor frame and look strange until the
next anchor frame occurs.  This of course assumes the format is robust
enough to determine where to pick up its frame timing in the data stream
in the first place.

2) As a result of #1, you can "preview" many formats by simply d/ling the
first part or few parts, then playing them to see if the entire file is
worth downloading.  Of course, this is mainly of interest to those with
slower connections or in extremely active groups.

3) Making explicit what the above implies, most formats will NOT work
without part one.  If you have part one, you can skip other parts with
some formats, but part one MUST be available.  (Of course if one is
downloading say an executable, attempting to skip a part isn't likely to
work anyway, but there's little need for such with Linux anyway, with so
many Linux apps available free for the download already.)

4) Note that /all/ parts need to have the same number of digits in the
extension for the above to get the order correct.  Thus .001-.009,.010...
will work, but .1-.9,.10-.99,.100-.999... will NOT work, without renaming
so the extensions line up.  The part ordering of the latter would be out
of order because cat will be combining in alphabetical order.  An
alternative to the renaming might be listing the ranges as necessary, tho
I've not tried it.

-- 
Duncan - List replies preferred.   No HTML msgs.
"They that can give up essential liberty to obtain a little
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