In Ubuntu 18.04 with GNOME, what is the command that is used to change the display brightness (backlight)?

2 Answers 2


xrandr can do this. Type in xrandr to find the name of the display that's connected it will likely be named whatever_interface_you_use-1. Then use

xrandr --output the_display_name --brightness brightness_level

With brightness-level being a number between 0 and 1. Don't type in 0 unless you want your screen to go black.

  • Thank you for your answer! The xrandr command corerctly changes the brightness, however what I meant by "brightness" was more like the display backlight. I should have stated that more clearly. Jul 5, 2019 at 7:43

You can use these commands in most if not all versions of gnome:

# Increase brightness:
gdbus call --session --dest org.gnome.SettingsDaemon.Power --object-path /org/gnome/SettingsDaemon/Power --method org.gnome.SettingsDaemon.Power.Screen.StepUp

# Decrease brightness:
gdbus call --session --dest org.gnome.SettingsDaemon.Power --object-path /org/gnome/SettingsDaemon/Power --method org.gnome.SettingsDaemon.Power.Screen.StepDown

If you have multiple monitors, you may be interested in this script which dims up to three monitors after 5 minutes of inactivity until mouse is moved or key is pressed. This is convenient when watching a movie on a second to fourth monitor (ie Big Screen TV).

At the very least the script will help you learn xrandr in general and how to change brightness using xrandr in great detail.

  • Thank you! These commands are exactly what I was looking for. And thanks for the script, might come handy some time. Jul 5, 2019 at 7:38

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