light1

Usage

Overview

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.