Redshift is an open-source screen color temperature adjustment tool that automatically adjusts the screen's color temperature based on time to reduce blue light stimulation and help protect eyesight. It works by adjusting the screen's color temperature according to the geographical location and time, transitioning smoothly to reduce eye strain. Redshift can be easily installed on Ubuntu with a simple command. Users can run Redshift through the command line or configure it via a file to set parameters such as latitude, longitude, day and night temperature, and transition. By adjusting settings like temp-day, temp-night, and location-provider, Redshift effectively protects eyes by regulating screen temperature.