How can I change brightness through terminal

Question

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

score 29 · Accepted Answer · edited Apr 13 '17 at 12:25

29

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.

edited Apr 13 '17 at 12:25

Community

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answered Aug 07 '11 at 17:06

sagarchalise

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it works (0-9 for me) – RiaD Aug 07 '11 at 17:31
See my comment on Michał Šrajer's post below for a way to alias this for easy use. – floer32 Nov 02 '12 at 12:24
How to change it? is not by `sudo nano /sys/class/backlight/acpi_video0/brightness` ... – Peter Krauss Dec 27 '17 at 14:05
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for me it was via `sudo vim /sys/class/backlight/intel_backlight/brightness` – Dara Java Aug 21 '18 at 22:11
Also, don't forget that instead of `vim`ing or `nano`ing to edit the file, you can simply `echo 15 > /sys/class/backlight/intel_backlight/brightness` – Damilola Olowookere May 17 '20 at 03:49
In my case it's `$ cat /sys/class/backlight/nvidia_wmi_ec_backlight/max_brightness` and `max_brightness` is 800. – Daniel Sep 02 '23 at 18:52

score 21 · Answer 2 · answered Aug 07 '11 at 17:25

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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

answered Aug 07 '11 at 17:25

fossfreedom

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+1, the only non requiring admin privileges – enzotib Aug 07 '11 at 20:49
So I was able to do this in the terminal in Ubuntu 15.04 with both the MATE and Unity desktops. However, when I bind this to any key combination it does not work. – HarlemSquirrel Apr 18 '15 at 01:03
This still works for XFCE on 15.04. – Jam Dec 11 '16 at 16:47
This still works (for me, at least) for XFCE on 18.04. Yet it doesn't allow to set to a fixed value, only steps up or down. – Stéphane Gourichon Jun 14 '18 at 20:32
I run `lxqt` on lubuntu 20_04, what should I write for `key`? `xdotool key XF86MonBrightnessDown` does not work. – Timo May 24 '21 at 18:23

score 14 · Answer 3 · edited Nov 12 '12 at 00:11

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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.

edited Nov 12 '12 at 00:11

sanderd17

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answered Oct 14 '11 at 20:50

Brallan Aguilar

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my notebook keyboard is broken, the external usb one has no key for that. the -dec option works, the -inc dont! but the -set does! so I will just create a simple script, thx!!! – Aquarius Power Jun 03 '17 at 03:31
Lubuntu 20_04 outputs `No outputs have backlight property`. – Timo May 24 '21 at 18:28

score 9 · Answer 4 · answered Aug 07 '11 at 16:51

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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

answered Aug 07 '11 at 16:51

Michał Šrajer

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have not /proc/acpi/video/ at all. find /proc/acpi -name 'brightness' prints nothing – RiaD Aug 07 '11 at 17:03
I think the command is `sudo sh -c` rather than `sudo su -c` – sagarchalise Aug 07 '11 at 17:07
@sagarchalise: it is more or less the same, `su` launch a `sh` – enzotib Aug 07 '11 at 20:50
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`sudo su -c 'echo 4 > /sys/class/backlight/acpi_video0/brightness'` worked for me. Using a Samsung laptop and oddly enough the range is 0-7. – floer32 Nov 02 '12 at 12:09
I tried to write a function to call this very easily - wound up with `function bri { sudo su -c 'echo $1 > /sys/class/backlight/acpi_video0/brightness';}` - but it didn't work for me. So as a substitute, I created aliases `bri0` through `bri7` which worked -- see [here](http://pastebin.com/ZX21bEvm). – floer32 Nov 02 '12 at 12:22
function brightness { sudo su -c "echo $1 > /sys/class/backlight/acpi_video0/brightness" } did the trick for me. – Max Wallace Mar 01 '15 at 19:14
Mine was under `/sys/devices/pci0000.../drm/card0/card0-eDP-1/intel_backlight/brightness`. `cd /sys; find -iname 'bright*'` is how I found it. – dhill May 25 '18 at 12:25

score 3 · Answer 5 · answered Aug 13 '15 at 11:02

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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.

answered Aug 13 '15 at 11:02

aibotnet

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score 3 · Answer 6 · edited May 31 '17 at 18:23

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"

Getting `Error org.freedesktop.DBus.Error.UnknownMethod: No such method “SetPercentage”` :( — Rohlik, Sep 29 '22 at 16:52

score 1 · Answer 7 · answered Jan 03 '14 at 02:00

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

answered Jan 03 '14 at 02:00

Stichoza

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score 1 · Answer 8 · answered May 16 '14 at 21:39

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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

answered May 16 '14 at 21:39

Muhammad Hewedy

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Binarylife · Answer 9 · 2011-08-07T17:17:44.113

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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.

edited Aug 07 '11 at 17:17

answered Aug 07 '11 at 17:05

Binarylife

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Do not work, here – enzotib Aug 07 '11 at 20:47
@enzotib : It works fine with me using 11.04. And I think it is only for a laptop. – Binarylife Aug 07 '11 at 20:55
Not working in DELL inspiron – totti Mar 27 '13 at 06:47
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Works on my Acer Aspire One – Karthik C Jul 07 '13 at 13:11
This is the only one that works for me on a Gateway / Packard Bell. – GenericJam Feb 20 '16 at 22:41
@Binarylife who do I undo this? Because I don't understand the command. I didn't think it changed my brightness. But the command ran without throwing an error. So, I wanted to undo this for future issues. – Pranav May 29 '21 at 07:26

How can I change brightness through terminal

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