GNOME Night Light Setting from the Command Line

Solution 1:

To turn on:

gsettings set org.gnome.settings-daemon.plugins.color night-light-enabled true

To turn off:

gsettings set org.gnome.settings-daemon.plugins.color night-light-enabled false

To schedule on time, here I want to schedule night light from 23:06 hrs (that is 06/60=0.1):

gsettings set org.gnome.settings-daemon.plugins.color night-light-schedule-from 23.1

To schedule off time, I want to schedule night light off at 23:25 hrs (that is 25/60=0.416666666):

gsettings set org.gnome.settings-daemon.plugins.color night-light-schedule-to 23.416666666

You can also set the night light temperature which will increase and decrease the brightness, 4000 is the default value for Ubuntu 18.04, you can try different values for example 2000, 3000, 5000, 6000, 10000 and set the preferred ones:

gsettings set org.gnome.settings-daemon.plugins.color night-light-temperature 4000

To get the current values for above commands, run the below commands

gsettings get org.gnome.settings-daemon.plugins.color night-light-enabled 
gsettings get org.gnome.settings-daemon.plugins.color night-light-schedule-from
gsettings get org.gnome.settings-daemon.plugins.color night-light-schedule-to
gsettings get org.gnome.settings-daemon.plugins.color night-light-temperature

Example:

$ gsettings get org.gnome.settings-daemon.plugins.color night-light-enabled
false
$ gsettings get org.gnome.settings-daemon.plugins.color night-light-schedule-from
23.1
$ gsettings get org.gnome.settings-daemon.plugins.color night-light-schedule-to
23.416666666000001
$ gsettings get org.gnome.settings-daemon.plugins.color night-light-temperature
uint32 1000
$