backlight_control

Increase/decrease the backlight by a specific percent count

$ backlight_control [+|-][5]

$ backlight_control [90]

$ backlight_control

backlight_control [-d DEVICE] [-g | -s VALUE | -i INC | -D DEC | --off | --on]

-d, --device
    Select backlight device (e.g., intel_backlight)

-g, --get
    Print current brightness level

-s, --set
    Set absolute brightness (0-max)

-i, --inc
    Increase brightness by VALUE

-D, --dec
    Decrease brightness by VALUE

--off
    Turn backlight off

--on
    Turn backlight on

-h, --help
    Show usage help

-l, --list
    List available backlight devices

backlight_control is a utility for managing backlight brightness on Linux systems, particularly laptops, embedded devices, and monitors supported by kernel drivers.

It interacts directly with the /sys/class/backlight/ subsystem to read current brightness, set absolute or relative levels, and toggle power states. This command simplifies scripting and hotkey bindings for brightness adjustments, often used in desktop environments like GNOME or i3.

Devices are identified by names like intel_backlight, acpi_video0, or kbd_backlight. Brightness values are typically in absolute units (0 to max_brightness) or percentages if supported.

Root privileges may be required for writes unless udev rules grant access to video/input groups. It's lightweight, dependency-free, and ideal for power management automation.

Requires write permissions to /sys/class/backlight/*; not all hardware supports relative changes or percentages. Conflicts may occur with desktop compositors or ACPI events.

Use ls /sys/class/backlight/ or backlight_control --list to find devices.
Read max brightness via cat /sys/class/backlight/DEVICE/max_brightness.

Add user to video group: gpasswd -a $USER video; logout/login required.

Introduced in early Linux kernel 2.6.x with sysfs backlight support; command variants appear in distro-specific utils since ~2010, evolving with ACPI and DRM drivers.

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