REDSHIFT(1)

🌸 REDSHIFT(1) — the manual page, but make it a group chat 🌸

okay bestie, gather round, because this is REDSHIFT(1) from the General Commands Manual and honestly? it's giving eye-saver, it's giving sleep-hygiene queen, and we're gonna go through it together. no skimming. i will know. 💅

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✨ NAME ✨

gammastep — sets the color temperature of your display according to the time of day. that's it. that's the whole vibe. 🌅

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✨ SYNOPSIS ✨

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

look at her. compact. efficient. main character energy. 👑

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✨ DESCRIPTION ✨

so gammastep adjusts the color temperature of your screen to match your surroundings. lowkey it's a whole wellness thing — it can help your eyes hurt less, and it can reduce the risk of delayed sleep phase syndrome if you're the type to be staring at a screen at night (no judgement, i am also that type 🫶).

the color temperature gets set according to the position of the sun. different temperature at night, different temperature during the day. and during twilight and early morning, the temperature transitions smoothly from night to daytime temp so your eyes get to slowly adapt over a period of about an hour. it's a slow burn. it's a character arc. 😭

at night, the color temperature should match the lamps in your room. that's typically a low temperature, 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). and heads up — the light has a higher temperature on an overcast day. the sky is doing side quests. ☁️

also! besides the command-line tool gammastep, there's a GUI called gammastep-indicator that gives you an alternative interface, showing up as a notification icon in your desktop environment. she's got range. 💖

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✨ OPTIONS ✨

• -h — display help message. the "what do i do" button.
• -v — enable verbose output. she will tell you everything.
• -V — show program version. number check.
• -b DAY:NIGHT — screen brightness to apply (between 0.1 and 1.0).
• -c FILE — load settings from the 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 results in more red light. the way the spectrum just... shifts. iconic. 🌈

default temperature values, periodt:

• Daytime: 6500K, night: 4500K

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✨ CONFIGURATION FILE ✨

a configuration file named 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). note the "optionally" — she's not demanding, she's just available. 🎀

the file has standard INI format. general program options go under the general header, while options for location providers and adjustment methods go 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. they're a package deal, bestie. 🫶
• 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. same deal, other direction. 🌙
• 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. go read the help output, she wrote it for you. 💜

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✨ EXAMPLE ✨

example for Copenhagen, Denmark 🇩🇰:

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

and here's an example configuration file with the same effect as the command line above — look at her matching, we love consistency:

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

[manual]
lat=55.7
lon=12.6

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✨ HOOKS ✨

okay this part is so fun. executables (e.g. scripts) placed in the 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. and any dotfiles in the folder are skipped. respect the hidden files' privacy. 🙈

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

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✨ AUTHOR ✨

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

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

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✨ BUGS ✨

please report bugs to <https://gitlab.freedesktop.org/CameronNemo/gammastep/issues> — she wants the feedback, bestie, it's not a burden, it's a gift. 🐛

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✨ 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. your little arrow stays its little arrow color, no cap. 💀

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and that's the whole page! this was REDSHIFT(1) from the General Commands Manual — no version bump, no fancy date stamp on the footer, just a plain <rainbow>REDSHIFT(1)</rainbow> sitting there at the bottom like a signature. mwah. go forth and protect your eyeballs. 🌸✨🎀🦋