Provided by: gammastep_2.0.9-1_amd64 bug

NAME

       gammastep - set color temperature of display according to time of day

SYNOPSIS

       gammastep [-l LAT:LON | -l PROVIDER:OPTIONS] [-t DAY:NIGHT] [OPTIONS...]

DESCRIPTION

       gammastep  adjusts  the  color  temperature of your screen according to your surroundings.
       This may help your eyes hurt less or reduce the risk for delayed sleep phase  syndrome  if
       you are working in front of the screen at night.

       The  color  temperature  is  set  according  to the position of the sun. A different color
       temperature is set during night and daytime. During twilight and early morning, the  color
       temperature  transitions  smoothly from night to daytime temperature to allow your eyes to
       slowly adapt over a period of about an hour. At night the color temperature should be  set
       to match the lamps in your room. This is typically a low temperature at around 3000K-4000K
       (default is 4500K). During the day, the color temperature  should  match  the  light  from
       outside,  typically  around  5500K-6500K  (default  is  6500K).  The  light  has  a higher
       temperature on an overcast day.

       In addition to the command-line tool gammastep, the GUI  gammastep-indicator  provides  an
       alternative interface that shows up as a notification icon in the desktop environment.

OPTIONS

       -h     Display help message.

       -v     Enable verbose output.

       -V     Show program version.

       -b DAY:NIGHT
              Screen brightness to apply (between 0.1 and 1.0).

       -c FILE
              Load settings from specified configuration file.

       -g R:G:B
              Additional gamma correction to apply.

       -l LAT:LON
              Your  current  location, in degrees, given as floating point numbers, towards north
              and east, with negative numbers representing south and west, respectively.

       -l PROVIDER[:OPTIONS]
              Select provider for automatic location updates (Use  "-l  list"  to  see  available
              providers).

       -m METHOD[:OPTIONS]
              Method to use to set color temperature (Use "-m list" to see available methods).

       -o     One-shot  mode (do not continuously adjust color temperature). Use this with the -P
              option to clear the existing gamma ramps before applying the new color temperature.

       -O TEMP
              One-shot manual mode (set color temperature).  Use this with the -P option to clear
              the existing gamma ramps before applying the new color temperature.

       -p     Print mode (only print parameters and exit).

       -P     Reset existing gamma ramps before applying new color effect.

       -x     Reset mode (remove adjustment from screen).

       -r     Disable fading between color temperatures.

       -t DAY:NIGHT
              Color temperature to set at daytime/night.

       The  neutral  temperature is 6500K. Using this value will not change the color temperature
       of the display. Setting the color temperature to a value higher than this results in  more
       blue light, and setting a lower value will result in more red light.

       Default temperature values:

              Daytime: 6500K, night: 4500K

CONFIGURATION FILE

       A   configuration   file   with   the   name   config.ini  can  optionally  be  placed  in
       ~/.config/gammastep/  (if  the  environment  variable  XDG_CONFIG_HOME  is  undefined)  or
       ${XDG_CONFIG_HOME}/gammastep/  (if  XDG_CONFIG_HOME is defined). The file has standard INI
       format. General program options are placed under the general  header,  while  options  for
       location  providers and adjustment methods are placed under a header with the name of that
       provider or method. General options are:

       temp-day = integer
              Daytime temperature

       temp-night = integer
              Night temperature

       fade = 0 or 1
              Disable or enable fading between color temperatures.

       brightness-day = 0.1-1.0
              Screen brightness at daytime

       brightness-night = 0.1-1.0
              Screen brightness at night

       elevation-high = decimal
              The solar elevation in degrees for the transition to daytime

       elevation-low = decimal
              The solar elevation in degrees for the transition to night

       dawn-time = HH:MM[-HH:MM]
              The custom time interval for the transition from night to day in the morning.  When
              specified,  the  solar  elevation  will  not  be  used  to  determine  the  current
              daytime/night period. If this option is set, dusk-time must also be specified.

       dusk-time = HH:MM[-HH:MM]
              The custom time interval for the transition from day to night in the evening.  When
              specified,  the  solar  elevation  will  not  be  used  to  determine  the  current
              daytime/night period. If this option is set, dawn-time must also be specified.

       gamma = R:G:B
              Gamma adjustment to apply (day and night)

       gamma-day = R:G:B
              Gamma adjustment to apply at daytime

       gamma-night = R:G:B
              Gamma adjustment to apply at night

       adjustment-method = name
              Select adjustment method. Options for the adjustment method can be given under  the
              configuration file heading of the same name.

       location-provider = name
              Select  location provider. Options for the location provider can be given under the
              configuration file heading of the same name.

       Options for location providers and adjustment methods can be found in the help  output  of
       the providers and methods.

EXAMPLE

       Example for Copenhagen, Denmark:

              $ gammastep -l 55.7:12.6 -t 5700:3600 -g 0.8 -m randr -v

       An example configuration file with the same effect as the above command line:

              [general]
              temp-day=5700
              temp-night=3600
              gamma=0.8
              adjustment-method=randr
              location-provider=manual

              [manual]
              lat=55.7
              lon=12.6

HOOKS

       Executables  (e.g.  scripts) placed in folder ~/.config/gammastep/hooks will be run when a
       certain event happens. The first parameter to the script indicates the event  and  further
       parameters  may  indicate  more  details  about  the  event.  The  event period-changed is
       indicated when the period changes (night, daytime, transition). The  second  parameter  is
       the old period and the third is the new period. The event is also signaled at startup with
       the old period set to none.  Any dotfiles in the folder are skipped.

       A simple script to handle these events can be written like this:

              #!/bin/sh
              case $1 in
                  period-changed)
                      exec notify-send "Gammastep" "Period changed to $3"
              esac

AUTHOR

       gammastep was written by Jon Lund Steffensen <jonlst@gmail.com>, and is now maintained  by
       Cameron Nemo <cam@nohom.org>.

       Both  gammastep  and  this  manual page are released under the GNU General Public License,
       version 3.

BUGS

       Please report bugs to <https://gitlab.freedesktop.org/CameronNemo/gammastep/issues>

KNOWN ISSUES

       gammastep will not affect the color of your cursor when your graphics driver is configured
       to use hardware cursors. Some graphics drivers have an option to disable hardware cursors.

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