[comp.unix.questions] how to defeat pipe buffering?

mkhaw@teknowledge-vaxc.UUCP (08/31/87)

Ultrix comes with a modified tar program called "mdtar" that can tar to
multiple volumes of physical media.  Mdtar writes both its "v" option output
and its prompt for the next volume on stderr.  I want to "tee" the output to
a log file and just grep for the prompt to show on the controlling terminal;
e.g., (omitting details of specifying media size)

	mdtar cv . |& tee /logdir/logfile | fgrep 'Please change'

but the pipe blocks trying to read my reply to the prompt before it prints
the prompt (to put it loosely).

Is there anything I can do to get the behavior I'm aiming for? (No, I don't
have source code, and yes, I've filed an SPR with DEC.)

Thanks,
Mike Khaw
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