As of now I’m migrating from Gnome to i3. Thus, when I hook up an external monitor to my laptop.

xrandr --output <monitor> --auto --above <primary monitor>

To list all connected monitors and find out what they’re called, you use “xrandr“. It will look something like this:

simon@tuxflux: xrandr

Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
eDP1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 282mm x 165mm
1920x1080     60.00*+  40.00
1400x1050     59.98
1280x1024     60.02
1280x960      60.00
1024x768      60.00
800x600       60.32    56.25
640x480       59.94
VGA1 disconnected (normal left inverted right x axis y axis)
HDMI1 connected (normal left inverted right x axis y axis)
1920x1080     60.00 +
1680x1050     59.88
1600x900      59.98
1280x1024     75.02    60.02
1280x800      59.91
1152x864      75.00
1280x720      59.97
1024x768      75.08    60.00
832x624       74.55
800x600       75.00    60.32
640x480       75.00    60.00
720x400       70.08
DP1 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

 

As you can see, my monitors’s called HDMI1 and eDP1. So to use my external monitor (HDMI1) right of my laptop, I fire:

xrandr --output HDMI1 --auto --right-of eDP1

Instead of “–right-of”, you could use:

--left-of <output>
--right-of <output>
--above <output>
--below <output>

To rotate the display left-side:

xrandr --output HDMI1 --rotate left

Instead of “–right-of”, you could use:

--left-of <output>
--right-of <output>
--above <output>
--below <output>