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Ubuntu 18.04 brightness/backlight command
July 5, 2019
Edited: July 5, 2019
November 24, 2022
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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.