Application that sets the backlight brightness on Linux machines.
The application uses the commands (brightness, actual_brightness,
max_brightness) under /sys/class/backlight/<device>. The device part is
specific to the video card in the host machine. The app tries to determine the
name automatically but it can also be explicitly given using the -cmd flag.
The application expects a percentage with which it should increase or decrease the brightness (accepted range: [-100 : 100]). It also prints the current and maximum values. If no percentage is given it only prints the values.
backlight [-cmd=<brightness commands directory>] [-p=<percentage>]
The application can be installed with the following command:
go install github.com/nagygr/backlight/cmd/backlight@latest
Please note, that this requires Go to be available on the system. It can be installed using the package manager of the host OS, e.g.:
pacman -S go # Arch Linux, Manjaro, etc.
dnf install golang # Fedora, Red Hat, etc.
apt-get install golang # Debian, Ubuntu, etc.Please note that, by default, the brightness file, which controls the
backlight brightness, can only be written by root. In order to make it
editable by an ordinary user, please create/edit the following file:
/etc/udev/rules.d/backlight.rules:
ACTION=="add", SUBSYSTEM=="backlight", RUN+="/bin/chgrp video $sys$devpath/brightness", RUN+="/bin/chmod g+w $sys$devpath/brightness"
This line allows the participants of the video group to set the backlight
brightness. Next, please add the user you wish to grant these rights to, to the
video group:
sudo usermode -aG video <user name>