REDSHIFT(1)

🌙 REDSHIFT(1) — the general commands manual, but make it cute

okay bestie, gather round, because this is the redshift page from the General Commands Manual and it's genuinely about to change your whole late-night screen situation 💖

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✨ NAME ✨

redshift — sets the color temperature of your display based on what time of day it is. that's it. that's the job. 🦋

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🌸 SYNOPSIS 🌸

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

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💫 DESCRIPTION 💫

so here's the vibe: redshift tweaks your screen's color temperature to match whatever's going on around you. why? because it might make your eyes hurt less, and it might reduce your risk for delayed sleep phase syndrome if you're the type to be up working in front of a screen at night. which. yeah. we know. 😭

the color temperature is set based on where the sun is. night and daytime get different temps, obviously. and during twilight and early morning, it transitions smoothly from night to daytime temperature so your eyes can slowly adapt — this whole glow-up takes about an hour. no abrupt jumps, we're not animals. 💅

at night, your color temp should match the lamps in your room — typically something low, like 3000K–4000K (default is 4500K). during the day, it should match the light from outside, typically around 5500K–6500K (default is 6500K). and fun fact: on an overcast day, the light has a higher temperature. clouds are out here being blue-light girlies. 🌈

also!! besides the command-line tool redshift, there's a GUI called redshift-gtk that gives you an alternative interface showing up as a notification icon in your desktop environment. main character energy, lowkey. 👑

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🎀 OPTIONS 🎀

• -h — show the help message. short king behavior.
• -v — turn on verbose output. she's chatty and we love that.
• -V — show the program version.
• -b DAY:NIGHT — screen brightness to apply, and it has to be between 0.1 and 1.0.
• -c FILE — load your settings from the specified configuration file.
• -g R:G:B — extra gamma correction to apply on top.
• -l LAT:LON — your current location, in degrees, as floating point numbers. north and east are positive; negative numbers mean south and west respectively. ✨
• -l PROVIDER[:OPTIONS] — pick a provider for automatic location updates. (run -l list to see what providers you've got, bestie.)
• -m METHOD[:OPTIONS] — the method used to set the color temperature. (run -m list to see available methods.)
• -o — one-shot mode, aka do not continuously adjust the 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, aka just set the color temperature, periodt. use this with the -P option to clear the existing gamma ramps before applying the new color temperature.
• -p — print mode. only prints the parameters and then exits. no notes, no drama. 🙈
• -P — reset existing gamma ramps before applying the new color effect.
• -x — reset mode. removes the adjustment from your screen entirely. we're so back to factory settings.
• -r — disable fading between color temperatures. no smooth transition, just vibes (or lack thereof).
• -t DAY:NIGHT — the color temperature to set at daytime/night.

k so important context: the neutral temperature is 6500K. using that value will not change the color temperature of your display. set it higher than that and you get more blue light; set it lower and you get more red light. that's the whole spectrum situation. 🌈

default temperature values, for the record:

• Daytime: 6500K, night: 4500K

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🦋 CONFIGURATION FILE 🦋

a configuration file named redshift.conf can optionally be placed in ~/.config/. it's in standard INI format, because we're organized like that. general program options live under the redshift header, while options for location providers and adjustment methods go under a header named after 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 when Redshift starts or stops.
• 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. and if this option is set, dusk-time must also be specified. they're a package deal, fr fr.
• 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. and if this option is set, dawn-time must also be specified. see above, same situation. 💜
• 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 the adjustment method. options for that adjustment method can be given under the configuration file heading of the same name.
• location-provider = name — select the location provider. options for that 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 themselves. go look, they're there. 🔍

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🌟 EXAMPLE 🌟

here's one for Copenhagen, Denmark — iconic city, iconic setup:

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

and an example configuration file that does the exact same thing as the command line above:

[redshift]
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 🌸

so this is the fun part. executables (scripts, bestie, scripts!) placed in the folder ~/.config/redshift/hooks will be run whenever a certain event happens. 👑

the first parameter to the script tells you which event it is, and further parameters may give more details about that event. the event period-changed is indicated when the period changes — and the periods are night, daytime, and transition. the second parameter is the old period and the third is the new period. the event also gets signaled when Redshift starts up, with the old period set to none. also: any dotfiles in that folder are skipped. not invited. 🚫

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

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💖 AUTHOR 💖

redshift was written by Jon Lund Steffensen <jonlst@gmail.com>. legend behavior, honestly.

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

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💀 BUGS 💀

please report bugs to <https://github.com/jonls/redshift/issues> — they want to hear from you, bestie, don't be shy.

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😭 KNOWN ISSUES 😭

redshift 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, so like… if that's you, go look. 🖱️✨

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okay that's the whole page!! 🫶 this was the redshift manual page, straight out of the General Commands Manual, and honestly it ate. go set your night temp to something cozy, protect your eyes, and hydrate. mwah. 💅🍓

— REDSHIFT(1), signing off ✨