Whilst working with Arduinos, every now and then I miss something that should have been really obvious and spend an hour in confusion. This error here was one of those:

avrdude: ser_open(): can't open device "": No such file or directory
ioctl("TIOCMGET"): Inappropriate ioctl for device
Problem uploading to board.  See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.

The above error would appear any time I tried to upload to my Arduino Yún. I thought maybe it was because my network wasn’t set up right or because I had misconfigured the Yún. Turns out it’s a very simple error to fix.

I just hadn’t changed the board setting in the Arduino editor. All I needed to do was go to Tools > Board > Arduino Yún. I had my Arduino Uno still set in there.

For me, it wasn’t as obvious that I’d forgotten this setting, as when connecting to the Arduino Yún via Wi-Fi, it comes up with “Arduino at (Arduino Yún)” under Tools > Port. So I didn’t realise it was still expecting an Arduino Uno board!

I’ve written this out in the hope that if someone else searches for that error and is in the same boat as me, this will help save em a little bit of time.