In the Arduino IDE on my RPi on the top there is a header that says, File, Edit, Tools and help.
Following a Magpi article it said to go to tools then serial port and change that depending on what board you use. The only problem is that it's not there, when I click tools I scroll down and there grayed out it says, serial port.
Why is this grayed out? And why can I not change it? Also, what port should be used for an Uno?