blight

Set display brightness to 50%

$ blight set [50] [[-r|--relative]]

$ blight show

$ blight max

$ blight inc [number] [[-r|--relative]]

$ blight dec [number]

blight [-h] [-l|-L] [-d DEVICE] <{get,set,add,sub}> [VALUE]

-h, --help
    Display usage help and exit

-l
    List all available backlight devices

-L
    List backlight devices with current/max brightness

-d DEVICE, --device DEVICE
    Specify backlight device (e.g., intel_backlight)

get
    Get current brightness percentage

set VALUE
    Set brightness to VALUE (0-100)

add VALUE
    Increase brightness by VALUE (0-100)

sub VALUE
    Decrease brightness by VALUE (0-100)

blight is a lightweight, dependency-free command-line utility for controlling screen backlight brightness on Linux systems. It interfaces directly with the kernel's /sys/class/backlight/ interface, allowing users to get, set, increase, or decrease brightness levels across multiple backlight devices. Ideal for scripts, keyboard shortcuts, or terminal users, it supports both absolute values (0-100%) and relative adjustments.

Unlike heavier tools, blight requires no external libraries and works out-of-the-box on most modern Linux distributions with sysfs support. It automatically detects available backlight devices but allows manual specification for multi-monitor or laptop setups. Brightness is normalized to a 0-100 percentage scale for consistency, regardless of hardware maximums.

Common use cases include binding to hotkeys (e.g., Fn keys via acpi events or xbindkeys), automating brightness in startup scripts, or quick CLI adjustments. It handles permissions gracefully, often working without root via uaccess rules, but may need udev tweaks for full functionality.

Requires write access to /sys/class/backlight/* (use sudo or udev rules); not all hardware exposes brightness controls; relative changes clamp at 0/100.

blight get → Current brightness
blight set 75 → Set to 75%
blight -d intel_backlight add 10 → Increase by 10%
blight -l → List devices

pip install blight or git clone https://github.com/r3pek/blight; often in AUR or distro repos as blight.

Developed around 2015 as a minimal Python script by user 'r3pek' on GitHub; gained popularity for its simplicity amid complex alternatives; later Rust ports emerged for better performance.

brightnessctl(1), light(1), xbacklight(1)