I probably didn't explain myself very well because many of you misunderstood
what I was asking - I didn't want to add more tar files to the tape I
wanted to append to the tar archive already on the tape (this is the tar
r option).
The command 'tar cfb - 20 files | rsh host dd of=/dev/rmt/0 obs=20b'
creates a tar achive on 'host', and I knew you could add additional tar
files by using the no-rewind option/and or the mt command. What I wanted
to do was to put that same tape in a week later (say) and add (append) to
the tar file on there already. So I end up with one tar file that gets
bigger and bigger rather than lots of little tar files.
It seems there is no way to do this on a remote tape drive using the Sun
version of tar. However gnu tar supports the host:/device option which
lets you go:
tar cvf host:/dev/rmt/0 files (creates a tar file on the tape)
tar rvf host:/dev/rmt/0 morefiles (adds more files to the end)
I downloaded version 1.12 of gnu tar and built it, and it works perfectly
despite the files being on a SunOS machine and the tape drive on a
Solaris machine.
Many thanks to you all, and especially those who figured out what I was
asking and recommeded gnu.
Chris
-- Dr Chris Stoddart: Unix SysAdmin, Department of Computer Science, Sheffield University, U.K.