xbacklight
Adjust screen backlight brightness
TLDR
Get current brightness
$ xbacklight
Set brightness$ xbacklight -set [40]
Increase brightness$ xbacklight -inc [25]
Decrease brightness$ xbacklight -dec [75]
Set with fade effect$ xbacklight -set [100] -time [60000] -steps [60]
SYNOPSIS
xbacklight [OPTIONS]
DESCRIPTION
xbacklight adjusts backlight brightness using the X RandR extension's backlight property. When called without arguments, it prints the current brightness level as a percentage. The -set, -inc, and -dec options modify the brightness.The -time and -steps parameters enable smooth fade transitions, spreading the brightness change over the specified duration.
PARAMETERS
-get
Print current brightness percentage (default when no action given).-set PERCENT
Set brightness to percentage.-inc PERCENT
Increase brightness by percentage.-dec PERCENT
Decrease brightness by percentage.-time MS
Fade duration in milliseconds.-steps N
Number of steps for fade.-display DISPLAY
X display to use.-help
Display help information.
INSTALL
sudo apt install xbacklight
sudo dnf install xbacklight
sudo apk add xbacklight
sudo zypper install xbacklight
nix profile install nixpkgs#xbacklight
CAVEATS
X11 only; does not work with Wayland. Requires the RandR backlight property to be exposed by the display driver. Many modern laptops and proprietary drivers (e.g., NVIDIA) do not expose this property. Use brightnessctl or light as more reliable alternatives that work via sysfs.
SEE ALSO
brightnessctl(1), light(1), xrandr(1)
