which is normally done on an Arduino using the serial monitor
You have several options for debugging a Attiny85 using the serial monitor
These options require that you connect a Serial/USB connector to the tiny when you want to communicate with it (and remove your programmer)TinyISP
With these you can leave all the wires from the programmer (Arduino) and use the serial monitor with a single command.
A big thank to Coding Badly for this solution.
The one that feels most Arduino-like is Serial-Relay in my opinion.