brightnessctl

A small utility to control device brightness.

brightnessctl reads and sets the brightness of backlights and keyboard LEDs through the standard Linux sysfs interface. The small binary is widely used as the back-end for laptop brightness keys on tiling-window-manager setups (i3, Sway, Hyprland, dwm), where the desktop environment's own brightness helper is absent.

The tool is written in C, runs without root by using udev-managed permissions on the relevant /sys/class/backlight directories, and supports both incremental ("5%+") and absolute ("set 60%") changes. A small companion library can be linked into other applications.

brightnessctl is Hummer12007's project, packaged in essentially every distribution. Most modern Wayland and minimal-X11 setups either pair it with a key-binding daemon (for example sxhkd or swayidle) or call it directly from compositor configuration. On GNOME and KDE, the desktop environment provides its own brightness service and brightnessctl is rarely needed.

License: MIT

Category: System

Website: https://github.com/Hummer12007/brightnessctl

Install

Debian/Ubuntu: sudo apt install brightnessctl
Fedora/RHEL:   sudo dnf install brightnessctl
Arch:          sudo pacman -S brightnessctl

Authors

Hummer12007

PreviousBrave Browser Nextbspwm