Expect

Too heavy - if you're looking for expect-like functionality but much simpler - look at empty (worst name in the world and impossible to search for - but great code): http://empty.sourceforge.net/

Here's a simple related tool I made: https://github.com/j3parker/hijack

It's like tee but also creates a named pipe that gets hooked into stdin.

It's pretty gross but in a pinch its been useful.

I looked right at the domain name, cotse.com, said to myself, "that sure looks real familiar..." and still failed to remember it. On a second look, it finally dawned on me, "Church of the Swimming Elephant!"

Pain in the behind as it is to use and debug, if implemented correctly, it actually works quite well. Used this back in the day for some automated distributed build and test, and performed admirably. Ahh, memories...