35

Now I can change it by Fn+ arrow right but now I need to do it via my shell script

RiaD
  • 1,395

9 Answers9

30

adding to what Michał Šrajer says in some cases the brightness may be controlled from /sys/class/backlight/acpi_video0/brightness as is the case with my dell vostro 3400 and my the brightness range is 0-15. You may have to look for other folder in /sys/class if the same path as mine doesnot exit.

Community
  • 1
sagarchalise
  • 24,306
21

In your script you can send the equivalent keystrokes that correspond to Fn+Right Arrow and Fn+Left Arrow i.e. Brightness Up and Down respectively

Install xdotool from the Software Center

Then in your script to increase brightness:

xdotool key XF86MonBrightnessUp

To decrease Brightness

xdotool key XF86MonBrightnessDown
fossfreedom
  • 174,526
14

You could install xbacklight package $sudo apt-get install xbacklight and then if you want to increase the brightness level, type $xbacklight -inc <level in a range of 10 - 100> and vice versa: $xbacklight -dec <level in a range of 10 - 100>.

Read xbacklight --help to see more options.

sanderd17
  • 191
Brallan Aguilar
  • 1,542
9

call:

sudo su -c 'echo 30 > /proc/acpi/video/VID/LCD0/brightness'

The path may be different in your system. To list all available call:

find /proc/acpi/video -name 'brightness'

To see possible values for each, just cat the file:

cat /proc/acpi/video/VID/LCD0/brightnes
Michał Šrajer
  • 28,899
3

Install xbacklight it is very light and useful.

sudo apt-get install xbacklight

Then use xbacklight -set 60 where number can varry from 0 to 100.

aibotnet
  • 131
3

Ubuntu's default desktop environment, Unity, has set of dbus methods that allow setting/getting brightness without need for sudo access.

Note well, that for this to work, one will need to have DISPLAY=:0 variable declared in the script.

Personally, I use qdbus application , with all the appropriate interface and method names combined into a nice function and store it in .bashrc

unityBrightness()
{ # change brightness in Unity/ Gnome
qdbus org.gnome.SettingsDaemon.Power\
      /org/gnome/SettingsDaemon/Power\
       org.gnome.SettingsDaemon.Power.Screen.SetPercentage "$1"

}

Usage of this function would be like : 

unityBrightness 50

, where 50 is the percentage.

Equivalent dbus-send command would be 

dbus-send --session --print-reply\
    --dest=org.gnome.SettingsDaemon.Power\
    /org/gnome/SettingsDaemon/Power \
    org.gnome.SettingsDaemon.Power.Screen.SetPercentage uint32:"$1"
Shakti Phartiyal
  • 558
Sergiy Kolodyazhnyy
  • 107,582
1

Here is a little utility to set brightness from terminal: linux-brightness-binary

Then you can set brightness like this: sudo bright 5 or sudo bright 0

0-15 works for me on Asus UX50V Laptop running Debian 7

Stichoza
  • 111
1

On Ubuntu trusty 14.04, this command works fine

sudo su -c 'echo 12 > /sys/class/backlight/acpi_video0/brightness'

You can change the value 12 to any value from 0 to 20

Thanks @Michał Šrajer and @sagarchalise

Muhammad Hewedy
  • 344
1

If you are using laptop.

You can use this command: sudo setpci -s 00:02.0 F4.B=xx

Which xx is the brightness in hex ranging from 0 (brightest) to FF (no brightness at all). I Use E0 when working on battery.

Binarylife
  • 16,662