Re: [Expectperl-discuss] pipeline question (fwd)

[Roland G. <r.g...@xs...>]

gl...@ma... wrote:

> I tried the change to the exec in Expect.  Didn't help.

Well, it helped insofar as you now can spawn pipe commands, right?

> Currently I am getting this:
> 
> Reached end of medium for /dev/nrmt1h; Please wait for file closing
> Cannot prompt (can't open /dev/tty): No such device or address

Hmm, this sounds bad.  'dd' is trying to read a user response
via /dev/tty, over which Expect doesn't have control.

interconnect() cannot help here, because as long as 'dd' is
reading from stdin, it has to open /dev/tty for a user respone.
[earlier programs tried to read from stderr, and this even worked,
on some systems... :-) ]

Workaround: don't pipe directly into 'dd', use an intermediate
file and spawn 'dd' separately.  Disadvantage: you need enough
harddiskspace.  Workaround for that: a named pipe:
'rsh ... > named_pipe' and 'dd if=named_pipe of=/dev/tape'

That way, 'dd's stdin stays available for user responses.  I do
hope that 'dd' is then using stdin and not stubbornly trying
to open /dev/tty, otherwise you've got a real problem.

> expect is catching the "Press RETURN ..." message, and happily changing
> tapes, but the
> 
> print $bakupcmdobj "\r";
> 
> which I do after the tape is ready is evidently failing.

Yes, because it goes to stdin and not to /dev/tty.

Hope this helps,

Roland
PS: Starting tomorrow, I'm off for summer vacation for two weeks.