Loglux

Loglux is a simple rust application with portable binaries to control brightness.

While heavily inspired by the original lux, it differs from it in one major aspect:

The brightness control is logarithmic - as we approach darker and darker brightness values the control step gets smaller and smaller.

It's perfect for us creatures of the night watching rust streams in complete darkness at 1AM as it allows us to make the laptop screen really dark.

Usage

loglux OPERATION [-p|--path (default: /sys/class/backlight)] [-n|--num-steps (default: 75)] [--no-notify]

• OPERATION is either up or down
• --path can be either a start directory containing multiple controllers, or a path to specific controller. In the directory case, the controller with the highest max_brightness setting will be selected.
• --num-steps is the only tunable parameter and it specifies the total number of steps for the adjustment scale. The default is tuned for steps of 9-10% near the maximum, then they'll get smaller and smaller as we approach the minimum.
• --no-notify skips the notification of the new value via notify-send.

Installation

Binaries for Linux on various architectures are available on the releases page.

They are statically linked against musl to completely reduce runtime dependencies.

Note

Your user must have write rights for the /sys/class/backlight/.../brightness file you're planning to use.

Your best bet is to do a ls -a /sys/class/backlight/*/brightness and check if it's owned by the video group and if the group has write rights.

If that's the case, simply add your user to the video group: sudo usermod -aG video $USER

For a more involved solution using udev you could first add your user to the wheel group:

sudo usermod -aG wheel $USER

Then define the udev rules to ensure the brightness file is writeable:

sudo tee /etc/udev/rules.d/99-loglux.rules <<EOF
RUN+="/bin/chgrp wheel /sys/class/backlight/intel_backlight/brightness"
RUN+="/bin/chmod g+w /sys/class/backlight/intel_backlight/brightness"
EOF

Finally, trigger udev:

sudo udevadm control --reload-rules && sudo udevadm trigger