Another [Expect] jewel, somewhere between [spawn] and
[interact].
http://www.cotse.com/dlf/man/expect/overlay.htm
outlines its functionality.

Also see http://expect.nist.gov/FAQ.html#q16

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I tried "overlay -0 $spawn_id -1 $spawn_id -2 $spawn_id tee" with the hope expect will exit and leave tee serve like a pipe optionally logging to file as well. But I get "tee: read error: Resource temporarily unavailable". Any ideas what's wrong?
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[Category Expect]