toggle gnome night light from shell or via keyboard shortcut

toggle-nightlight.sh

#!/usr/bin/env bash
set -euo pipefail

BUS_NAME="org.gnome.SettingsDaemon.Color"
OBJECT_PATH="/org/gnome/SettingsDaemon/Color"

TRUE="variant:boolean:true"
FALSE="variant:boolean:false"

set_disabled() {
  dbus-send --session --dest=$BUS_NAME --print-reply $OBJECT_PATH \
    org.freedesktop.DBus.Properties.Set string:$BUS_NAME \
    string:DisabledUntilTomorrow "$1" >> /dev/null
}

get_disabled() {
  dbus-send --session --dest=$BUS_NAME --print-reply=literal $OBJECT_PATH \
    org.freedesktop.DBus.Properties.Get string:$BUS_NAME \
    string:DisabledUntilTomorrow | awk '{print $3}'
}

status=$(get_disabled)

case $status in
  true) set_disabled $FALSE ;;
  false) set_disabled $TRUE ;;
  *) echo "unknown result when trying to get disabled status: \"$status\"" 1>&2; exit 1 ;;
esac