NAME

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

SYNOPSIS

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

DESCRIPTION

       redshift 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 3700K). During the day, the color temperature  should  match  the  light  from
       outside,  typically  around  5500K-6500K  (default  is  5500K).  The  light  has  a higher
       temperature on an overcast day.

OPTIONS

       -h     Display this help message

       -v     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)

       -O TEMP
              One shot manual mode (set color temperature)

       -p     Print mode (only print parameters and exit)

       -x     Reset mode (remove adjustment from screen)

       -r     Disable temperature transitions

       -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: 5500K, night: 3700K

CONFIGURATION FILE

       A  configuration  file  with  the  name  `redshift.conf'  can  optionally  be  placed   in
       `~/.config/'.  The  file has standard INI format. General program options are placed under
       the `redshift' 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

       transition = 0 or 1
              Disable or enable transitions

       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 for the transition to daytime

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

       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:

              $ redshift -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:

              [redshift]
              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/redshift/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  when
       Redshift  starts  up  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 "Redshift" "Period changed to $3"
              esac

AUTHOR

       redshift was written by Jon Lund Steffensen <jonlst@gmail.com>.

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

BUGS

       Please report bugs to <https://github.com/jonls/redshift/issues>

KNOWN ISSUES

       Redshift  won't 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  in
       xorg.conf.