This program allows you read and control device brightness. Devices, by default, include backlight and LEDs (searched for in corresponding classes). If omitted, the first found device is selected.

It can also preserve current brightness before applying the operation (allowing for usecases like disabling backlight on lid close).


The program is available in: * Alpine Linux - starting with 3.11 and Edge * Arch Linux * Void Linux * Debian - starting with Buster (and derivatives) * Ubuntu - starting with 18.04 (and derivatives) * openSUSE - available in Tumbleweed, use OBS utilities/brightnessctl devel project for Leap < 15.1 * Fedora/EPEL (orphaned, deleted since F30, maintainer wanted) * NixOS/nix - starting with 17.09, please see the NixOS Wiki page for the "best-practice" configuration file based installation

One can build and install the program using make install. Consult the Makefile for relevant build-time options.


Modifying brightness requires write permissions for device files or systemd support. brightnessctl accomplishes this (without using sudo/su/etc.) by either of the following means:

1) installing relevant udev rules to add permissions to backlight class devices for users in video and leds for users in input. (done by default)

2) installing brightnessctl as a suid binary.

3) using the systemd-logind API.

The behavior is controlled by the INSTALL_UDEV_RULES flag (setting it to 1 installs the udev rules, it is the default value).

The systemd support (since v243) is controlled by the ENABLE_SYSTEMD flag (udev rules will not be installed by default).


``` Usage: brightnessctl [options] [operation] [value]

Options: -l, --list list devices with available brightness controls. -q, --quiet suppress output. -p, --pretend do not perform write operations. -m, --machine-readable produce machine-readable output. -n, --min-value set minimum brightness, defaults to 1. -e, --exponent[=K] changes percentage curve to exponential. -s, --save save previous state in a temporary file. -r, --restore restore previous saved state. -h, --help print this help. -d, --device=DEVICE specify device name (can be a wildcard). -c, --class=CLASS specify device class. -V, --version print version and exit.

Operations: i, info get device info. g, get get current brightness of the device. m, max get maximum brightness of the device. s, set VALUE set brightness of the device.

Valid values: specific value Example: 500 percentage value Example: 50.5% specific delta Example: 50- or +10 percentage delta Example: 50%- or +10% ```