avrdude: ser_open(): can't open device "/dev/ttyACM0": Permission denied ioctl("TIOCMGET"): code example

Example: avrdude: ser_open(): can't open device "/dev/ttyACM0": Permission denied ioctl("TIOCMGET"):

# On a terminal:

#If you use Ubuntu, Debian etc...
sudo adduser <yourname> dialout

# If you user Arch Linux...
sudo gpasswd -a <yourname> dialout

#then

sudo chmod a+rw /dev/ttyACM0