Linux Ubuntu i3 multi-monitor support using xrandr

multi_monitors.sh

# https://i3wm.org/docs/userguide.html#multi_monitor

# (AUTO) to auto setup
$ xrandr --auto

# if the position is not correct, then manually setup by first listing all the monitors
$ xrandr 
Screen 0: minimum 320 x 200, current 2880 x 1800, maximum 16384 x 16384
eDP connected primary 2880x1800+0+0 (normal left inverted right x axis y axis) 331mm x 207mm
   2880x1800     59.99*+
   1920x1200     59.95  
   1920x1080     60.00  
   1600x1200     59.95  
   1680x1050     60.00  
   1400x1050     60.00  
   1280x1024     59.95  
   1440x900      59.99  
   1280x960      59.99  
   1280x854      59.95  
   1280x800      59.96  
   1280x720      59.97  
   1152x768      59.95  
   1024x768      59.95  
   800x600       59.96  
   848x480       59.94  
   720x480       59.94  
   640x480       59.94  
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-1 disconnected (normal left inverted right x axis y axis)
HDMI-0 connected (normal left inverted right x axis y axis)
   3840x2160     30.00 +  25.00    24.00    29.97    23.98  
   4096x2160     30.00    25.00    24.00    29.97    23.98  
   1920x1080     60.00    50.00    59.94    30.00    25.00    24.00    29.97    23.98  
   1920x1080i    60.00    50.00    59.94  
   1680x1050     59.88  
   1600x900      60.00  
   1280x1024     75.02    60.02  
   1440x900      59.90  
   1366x768      59.79  
   1280x800      59.91  
   1152x864      75.00  
   1280x720      60.00    50.00    59.94  
   1024x768      75.03    70.07    60.00  
   832x624       74.55  
   800x600       72.19    75.00    60.32  
   720x576       50.00  
   720x576i      50.00  
   720x480       60.00    59.94  
   720x480i      60.00    59.94  
   640x480       75.00    72.81    66.67    60.00    59.94  
   720x400       70.08  
   
# or list active monitors only 
$ xrandr --listactivemonitors
Monitors: 2
 0: +*eDP 2880/331x1800/207+0+0  eDP
 1: +HDMI-0 3840/1872x2160/1053+0+0  HDMI-0


# (SECOND DISPLAY) place second HDMI screen to the right of main screen
$ xrandr --output HDMI-0 --auto --right-of eDP

# (MIRROR DISPLAY) mirror main screen on second display
$ xrandr --output HDMI-0 --auto --same-as eDP

# (TURN OFF SECOND DISPLAY) 
$ xrandr --auto --output HDMI-0 --off

# (TURN OFF MAIN DISPLAY) 
$ xrandr --auto --output eDP --off