xrandr

Set the size, orientation and/or reflection of the outputs for a screen. More information: https://www.x.org/releases/current/doc/man/man1/xrandr.1.xhtml.

• Display the current state of the system (known screens, resolutions, …):

xrandr --query

• Disable disconnected outputs and enable connected ones with default settings:

xrandr --auto

• Change the resolution and update frequency of DisplayPort 1 to 1920x1080, 60Hz:

xrandr --output DP1 --mode 1920x1080 --rate 60

• Set the resolution of HDMI2 to 1280x1024 and put it on the right of DP1:

xrandr --output HDMI2 --mode 1280x1024 --right-of DP1

• Disable the VGA1 output:

xrandr --output VGA1 --off

• Set the brightness for LVDS1 to 50%:

xrandr --output LVDS1 --brightness 0.5

• Display the current state of any X server:

xrandr --display :0 --query