xbacklight

XBACKLIGHT(1)               General Commands Manual              XBACKLIGHT(1)



NAME
       xbacklight - adjust display and keyboard backlight using the /sys
       filesystem

SYNOPSIS
       xbacklight [-h|-help] [-ctrl CTRL] [-display IGNORED] [-time MILLISECS]
       [-steps STEPS | -fps FPS] ...

       xbacklight [flags] -list
       xbacklight [flags] -get | -getf
       xbacklight [flags] -set PERCENT | -inc PERCENT | -dec PERCENT
       xbacklight [flags] [=]PERCENT | +PERCENT | -PERCENT

DESCRIPTION
       xbacklight can query or set the brightness of display and keyboard
       backlight.  xbacklight operates on the first device found in
       /sys/class/backlight, unless told otherwise. Use -list to see the full
       list of available devices that can be used; then use the -ctrl flag to
       control them individually.

QUERY OPERATIONS
       -list  Print the list of controllable devices.

       -get   Print out the backlight brightness as a percentage.

       -getf  Same as -get, but without rounding.

SET OPERATIONS
       The brightness can be set with either command flags or positional
       arguments.  When changing brightness level, both integer and fractional
       values (as reported by -get and -getf respectively) are accepted.

       Regular set flags:

       -set PERCENT
              Sets the backlight brightness to the specified percentage level.

       -inc PERCENT
              Increases brightness by the specified amount.

       -dec PERCENT
              Decreases brightness by the specified amount.

       Set operations using positional arguments:

       xbacklight PERCENT
       xbacklight =PERCENT
              Set brightness (same as -set PERCENT).

       xbacklight +PERCENT
              Increase brightness (same as -inc PERCENT).

       xbacklight -PERCENT
              Decrease brightness (same as -dec PERCENT).

OPTIONS
       -h, -help
              Print out a summary of the usage and exit.

       -time MILLISECONDS
              Length of time to spend fading the backlight between old and new
              value.  Default is 200. Specifying either the number of fading
              steps (with -steps) or fading frame rate (with -fps) is required
              to actually perform fading.

       -steps STEPS
              Number of fading steps.

       -fps FPS
              Target frame rate (frames/steps per second).

       -display IGNORED
              Ignored for backward compatibility.

       -ctrl CONTROLLER
              Set the device name to operate on.

NOTES
       xbacklight doesn't lock the backlight device during fading. Running two
       concurrent fading operations will result in backlight flickering.

       The backlight of most panels cannot be changed at a rate higher than
       20-30hz.  Setting a high FPS value will not improve the transition
       smoothness beyond a certain point.

       Most keyboard's backlights have a very coarse resolution, with usually
       only 4 brightness steps available. Supplying small relative increments
       will not effectively change the backlight illumination. Use large
       values (+30) or set absolute percentages directly (=70).

PORTABILITY
       This version of xbacklight is part of "acpilight" and contains several
       enhancements not available in the original version:

       The command-line flags -list, -ctrl, -getf and -fps do not exist in the
       original xbacklight.

       Fractional values are not allowed in the original xbacklight.

       The = (equals) is required by the original version when specifying an
       absolute brightness value, but can be omitted in this version.

AUTHORS
       xbacklight is part of acpilight (https://gitlab.com/wavexx/acpilight)
       and is distributed under GPLv3+ WITHOUT ANY WARRANTY.
       Copyright(c) 2016-2018 by wave++ "Yuri D'Elia" <wavexx@thregr.org>.



                                      1.0                        XBACKLIGHT(1)