I have a problem with my laptop (Acer Aspire 5750G), I can't change the screen brightness. I noticed that the only application with which I was able to change the brightness of my laptop screen is xrandr. However it seems to not work correctly. It seems to decrease the brightness in color, not in the backlight of the laptop strength. I wasn't completely sure at first, but I tested it now with black color, and there is no decrease in the darkness of black, because the backlight never decreases, just the colors get darker if you decrease this brightness.

I think a lot of people on the forums failed to notice this phenomenon, however it's real. And it's bad, it does affect the eyes negatively as well as the battery performance.

Can anybody tell me how to decrease the brightness in terms of the laptop screen backlight strength?


OK, seems I figured out how to change the brightness after all, all you have to do is:

echo 100 | sudo tee /sys/class/backlight/intel_backlight/brightness

the path should be /sys/class/backlight/ and whatever the path is relevant for your monitor.

the echo 100 is the amount for the screen brightness, I think max is 976 or something, I don't know what the lowest is, might be 1 or something, but this finally worked for me, despite browsing countless forums and stack questions I finally found it.

EDIT: decided I'd like to share with you, how I modified my discoveries to make the brightness increase and decrease when called:

$ screenlight=`cat /sys/class/backlight/intel_backlight/brightness`; echo `expr $screenlight - 100`  | sudo tee /sys/class/backlight/intel_backlight/brightness 


The 100 in here can be replaced with any suitable value for you, with 100 you would have approximately 10 brightness steps.

Now you can just map this command to a keyboard key or keyboard shortcut and you have a working screen brightness control on your laptop...

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