Use dmseg | tail to figure out what port the USB is after plugging in the USB device.
echo "Hello world" > /dev/USB0 and echo "Hello World" > /dev/ACM0 depending on the USB device used.
The above seems to a good way to determine permissions. You can also watch for an Rx LED to blink on the board when you execute the cmd and it succeeds. At least you'll get errors that make more sense than from the IDE.
You may