Subj : perl files for fidonet
To   : Russ Johnson
From : Jasen Betts
Date : Sun Jul 01 2001 02:13 am

Hi Russ.

28-Jun-01 17:03:58, Russ Johnson wrote to Maurice Kinal


 >> That makes at least two of us as I am IP only as well.  If you'd
 >> like to try
 RJ> >doing something different besides just the archiving I'd be game
 RJ> pointing unde
 >> you but would appreciate starting out doing that and then see where
 >> it can go from there.  I still have a node and another point (I am
 >> currently responding
 RJ> >using that) so as far as being in step with the rest of Fido I am
 RJ> covered twic
 >> over.  It be nice to do some experimentation using Perl and offhand
 >> an idea like this might prove to be interesting and perhaps even
 >> fun.  What do you think?

 RJ> I just had a discussion with the author of bbbs. According to him,
 RJ> the reason you can't use tar.gz as an echomail archiver is because
 RJ> it can't append to an archive. This makes sense, since tar is used
 RJ> for writing to tape.

actually it can append because it's for writing to a "raw" tape and you might
want to put a full and a bunch of incremental backups on a single tape
withouth having to rewind the tape each time ...

gzip copmpression is also append friendly, as was "compress" (and probably
"pack") compreesion before it. (unix compress not microsoft compress)

As a result of these two facts you can simply append tar.gz files!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# you could do this
cat *.tar.gz  > somewherelse/onehugefile.tar.gz

# or you can do it with redirection as the files are formed.
# eg  (unix only, under dos using ">>" on binary files will mess things up)
tar -czf- somefiles/*   >> file.tar.gz
tar -czf- otherfiles/*  >> file.tar.gz

(in dos you have to use  "copy /b"  to concatenate the files)

When it's time to get the stuff out all you need extra is the 'i'switch to
tar when you're untarring the appended tar archive. (without the i tar will
stop ar the end of the first part)

# this will list all the files
tar -tivzf file.tar.gz

# this will extract all the files
tar -xizf file.tar.gz

You do lose some compression efficiency as the archive is compressed in
chunks rather than as a seemless whole, but if that's a big deal it can be
fixed by uncompressing and recompressing it.

# like this
gunzip file.tar.gz ; gzip file.tar.gz

 -=> Bye <=-

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 * Origin: Forty two!  What was the question? (3:640/531.42)

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