HOW TO UPLOAD A SKETCH ON LINUX ENVIORNMENT IF ERROR HAS OCCURED
It might happen that when you upload a sketch - after you have selected your board and the serial port -, you get an error Error opening serial port … If you get this error, you need to set serial port permission.
Open Terminal and type:
$ ls -l /dev/ttyACM*
you will get something like:
$ crw-rw---- 1 root dialout 188, 0 5 apr 23.01 ttyACM0
The “0” at the end of ACM might be a different number, or multiple entries might be returned. The data we need is “dialout” (is the group owner of the file).
Now we just need to add our user to the group:
$ sudo usermod -a -G dialout $USER
$USER will default to the logged in Linux user name. You will need to log out and log in again for this change to take effect.