Redshift is an open-source screen color temperature adjustment tool that automatically adjusts the screen color temperature based on time to reduce the stimulation of blue light to the eyes, helping users better protect their vision. It works by adjusting the screen color temperature according to geographic location and time, supporting manual settings of latitude, longitude, and color temperature parameters with smooth transitions. Redshift can be easily installed on Ubuntu through command line or configuration file methods, providing flexibility in setting daytime and nighttime color temperatures, transition effects, and location parameters for personalized eye protection.