brightnessctl

This shell project is designed to allow change of the /sys/class/backlight/*/brightness without being root. This is usefull for keybinding.

Configuration

By default, it is configured to use intel backlight, as present in configuration.sh

brightFolder="/sys/class/backlight/intel_backlight/"

This path may not be present in every environment. So, to get the correct path, navigate to /sys/class/backlight and search for the file with name = brightness.

$ pwd
/sys/class/backlight

$ ls -ltr
lrwxrwxrwx 1 root root 0 Mar 20 14:20 radeon_bl0 -> ../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/drm/card0/card0-LVDS-1/radeon_bl0

$ find .  -maxdepth 2 -name 'brightness' -type f -follow
./radeon_bl0/brightness
find: File system loop detected; ‘./radeon_bl0/subsystem’ is part of the same file system loop as ‘.’.

and update the value in configuration.sh before executing sudo make install.

brightFolder="/sys/class/backlight/radeon_bl0/"

Installation

Installation is mostly done by the small makescript I wrote. However setting this up for i3 and edditing the sudoers file needs to be done manually.

$ sudo make install

Make sudo not ask for a password

The script needs to be able to be run as root without sudo asking for a password (otherwise you can't keybind it).

$ sudo visudo

and insert the following line

%wheel ALL=(root) NOPASSWD: /usr/local/bin/brightness

In my case the sudoers group is equal to wheel.

Testing

! be warned, a brightness of 0 made my screen completly black in the passed, 
! use arrow up to get the 100 command again

Now type in (be warned, a brightness of 0 made my screen completly black in the passed, use arrow up to get the 100 command again)

$brightness 100
$brightness 0

The birghtness should have chagned. Now you can setup keybindings to this script for your favorite window manager!

Key binding (i3)

If you use i3 you could use the following lines in your config to fix keybinding:

bindsym $mod+F8 exec brightness-
bindsym $mod+F9 exec brightness+