OKOKOK ....I'm newbie to working with serial, the first time I needed to do something with this!
I did the way it is because I was following some tutorials, one of them said that I should set -1 to disable what I will not use in serial communication, how I want to send serial information from Attiny to arduino I decided to activate TX only (it's it which sends the information, right?) and connected to the Uno RX for it to receive and send that information to the computer.
Questions:
1 - The Uno that I use to program can be used to see the serial output or should I connect the attiny to another Uno that excuta a code just to get data that it receives via serial and prints to the monitor?
2 - I was to make the attiny TX connection on PB0 and "const int tx = 2;" change to 0 instead of 2 and continue connecting the RX-0 port on Uno?
Reading the answers again, I was doubting you understood what this code is, it is the code that runs on Attiny85 and what is running on Uno is the ISP code to record on Attiny.