Yes, I want the script to accept incoming connections over telnet and take one line of input, process that input, display the script's standard-out over the telnet connection. I still don't see how netcat pipes items into my script AND then pipes back the results.
I really don't want root running this script for security reasons, hence why I chose port 1234 for my example.
This will cause netcat to run /bin/cat whenever something connects to it, feeding the sockets input into cat, and feeding cat's output back into the socket. Try telnetting to localhost port 9000 1234 and typing lines into it, it'll spit them back to you. ( but be sure to keep a way to kill nc handy as telnet won't know when to quit!).