Ubuntu / Mint Linux - No ports detected in Arduino IDE

gistfile1.txt

sudo ls -l /dev/ttyACM* /dev/ttyUSB*

# if the above command returns "No such file or directory" for both /dev/ttyACM* and /dev/ttyUSB* try disabling or uninstalling brltty and reboot.

sudo apt purge brltty

or
 
sudo systemctl stop brltty-udev.service
sudo systemctl mask brltty-udev.service
sudo systemctl stop brltty.service
sudo systemctl disable brltty.service

If there are /dev/ttyACM* or /dev/ttyUSB* devices they try the following:

# add user to dialout group
sudo usermod -a -G dialout $USER
# then logout and in again