linusrachlis / redshift-continuous

Cron bash script to cycle redshifting at arbitrary times

Note, the Redshift author has implemented a new feature for custom dawn/dusk times (jonls/redshift#529), which will make this script obsolete.

Cron script for continuous Redshifting at arbitrary times

This is designed to work with Redshift: https://github.com/jonls/redshift

Uses bc for math, only other dependencies are bash and redshift as mentioned above.

Example crontab setup

I've set it up like this:

cd
mkdir bin
cd bin
ln -s <repo path>/redshift-continuous.sh

This will run it every 5 minutes. By default it will tween the screen temperature from 7-8am for dawn, and 9-10pm for dusk. You can change this by editing the 'case' block within the script.

*/5 * * * * /home/<username>/bin/redshift-continuous.sh >> /home/<username>/redshift-continuous.log 2>&1

Example systemd.timer setup

For those of us stuck using systemd or like me too lazy to install a cron replacement, this is how i make things work:

In ~/.config/systemd/user/redshift-continuous.service:

[Unit]
Description=Continuously interpolate Redshift colour temperature

[Service]
Type=oneshot
StandardOutput=syslog
StandardError=syslog
ExecStart=/home/USERNAME/bin/redshift-continuous.sh

In ~/.config/systemd/user/redshift-continuous.timer:

# Because of the filenames matching, no need to point explicitly to
# the service file.
[Unit]
Description=Run redshift-continuous.service every 5 minutes

[Timer]
# Every 5 minutes:
OnUnitActiveSec=5m

[Install]
WantedBy=timers.target

Now, run the following commands to make it all work:

systemctl --user daemon-reload
systemctl --user enable redshift-continuous.service
systemctl --user enable redshift-continuous.timer

This is equivalent to the crontab-style setup above.