$ brightnessctl -device='tpacpi::kbd_backlight' set 1 This will show the absolute and relative current value and the maximum absolute value. $ brightnessctl -device='tpacpi::kbd_backlight' info When using brightnessctl you can get a list of available brightness controls with brightnessctl -list, then to show the kbd backlight information: # echo 1 > /sys/class/leds/tpacpi::kbd_backlight/brightness $ cat /sys/class/leds/tpacpi::kbd_backlight/max_brightness For example to get the maximum brightness level: The current brightness level can be get by reading /sys/class/leds/tpacpi::kbd_backlight/brightness. The sys pseudo-file system exposes an interface to the keyboard backlight. There are a variety ways to manage the brightness level and different helpers tools to accomplish this, such as brightnessctl or light.
There are various methods to control the keyboard backlight brightness level.