---
name: "light"
section: "1"
platform: "linux"
package: "light"
version: "1.2.2-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/light"
---

# light(1)

a program to control backlight controllers

## NAME

**light** – a program to control backlight controllers

## SYNOPSIS

**light** \[*OPTIONS*\] \[*VALUE*\]

## DESCRIPTION

**light** is a program to control backlight display and keyboard controllers under GNU/Linux.

- Operates independently of X (X-Window)

- Can automatically figure out the best controller to use, making full use of the underlying hardware

- Supports a minimum cap on the brightness value, as some controllers set the display to be pitch black at a vaĺue of 0 (or higher)

## COMMANDS

The following unique commands are supported:

- **-H**, **-h**

  Show help text and exit

- **-V**

  Show program version and exit

- **-L**

  List available devices

- **-A**

  Increase brightness by value

- **-U**

  Decrease brightness by value

- **-S**

  Set brightness to value

- **-G**

  Get brightness, default

- **-N**

  Set minimum brightness to value

- **-P**

  Get minimum brightness

- **-O**

  Save current brightness

- **-I**

  Restore previously saved brightness

## OPTIONS

The behavior of the above commands can be modified using these options:

- **-r**

  Interpret input and output values in raw mode

- **-s** *PATH*

  Specify device target path.  Use **-L** to list available devices

- **-v** *LEVEL*

  Set verbosity level, by default **light** only outputs read values:

  - 0:

    Read values

  - 1:

    Read values, Errors

  - 2:

    Read values, Errors, Warnings

  - 3:

    Read values, Errors, Warnings, Notices

## FILES

When run in its classic SUID root mode **light** caches settings and current brightness in */etc/light*. In its non-privileged mode of operation the *~/.cache/light* directory is used instead.

## AUTHORS

Copyright © 2012-2018 Fredrik Haikarainen

This is free software, see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE