Jay Lessert wrote:

#!/bin/sh
mt -f /dev/nrsa1 rewind
mt -f /dev/nrsa0 rewind
filenum=0
while true ; do
    echo copying tape file number $filenum
    dd bs=32k if=/dev/nrsa1 of=/dev/nrsa0 || exit
    filenum=`expr $filenum + 1`
done

I assume dd will return fail status when /dev/nrsa1 hits EOM, but
I've not tested that; keep an eye on it.  IIRC, your total number
of files should be #DLEs + 2.

Yes, dd will return "fail" when /dev/nrsa1 hits EOM, but also when
/dev/nrsa0 (your output tape) has a write error (basically there is
no much difference between End-Of-Media and a write error).
Somehow you have to check if you got hit by an error on which tape
device, be it by first counting the files on tape /dev/nrsa1,
be it by seperating the reading and the writing, maybe something like:


while :
do {dd ibs=32k if=/dev/nrsa1  ||  exit} |
   {dd obs=32k if=/dev/nrsa0  ||  echo 'Write error' >&2}
done

Untested -- adding rewind and filenum feedback is up to the user.
Notice the curly braces instead of parenthesis, or 'exit' would only
exit the subshell; this needs a modern shell (bash/ks will do).

--
Paul Bijnens, Xplanation                            Tel  +32 16 397.511
Technologielaan 21 bus 2, B-3001 Leuven, BELGIUM    Fax  +32 16 397.512
http://www.xplanation.com/          email:  Paul.Bijnens AT xplanation DOT com
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