I am just digging into Tom Igoe's kick'n book but am running into a little issue.
By happy coincidence I happen to have a copy of his book nearby--well, more due to the local library. (It was total luck I found it though, it wasn't catalogued under computers or electronics it was under robotics--in a third, completely separate physical shelf location...)
You're actually missing something important, but from looking at the text I can see how easily you could.
What you need to type is:
screen /dev/tty.usbserial-A4000PBA 9600
You're missing the actual command you need, in this case screen which--in the book--is printed in a different colour (black--the same colour as the text) to the parameters (purple). I can see how you'd miss it.
The reason you get "Permission denied" is probably because you're telling the computer to try to execute the serial port as a command. (It could also be because you don't have permission to access the port--which may mean you still get the same permission error when you use the correct command.)
Oh sheesh! .... Can't tell you how many times I looked at that. That works Great now! Thank you so very much!
Guess there lies the problem with reading 30 pages ahead then going back to try the experiments.
Currious though, are you saying that my question prompted you to go to the library to get the book?
Wow, doubly thanks then.
Gotta say, this book is going to fill in a lot of the missing information for me. At least it is going to get me started.