oky is a command line program to control an onkyo receiver. It works by receiving and sending ISCP commands to the receiver over a socket.

This project includes 2 files
    onkyo.py:  a library implementing the protocol to communicate with the onkyo receiver
    oky: a command line interface to onkyo.py

It has been developed for and tested with an Onkyo TX-NR609 but using older documentation for serial interface so it should in theory works with many models.
Only the subset of commands I have use for are implemented, it is however used almost every day and stable