Redshift is a app for managing brightness of screen for day and night for linux, mac, windows

for installing redshift on linux just type this statement in terminal

sudo apt-get install redshift redshift-gtk

redshift_settings

manuel redshift settings for screen

Go to home directory and in the directory '.config' make file by the name 'redshift.config' and paste the content of 'redshift.conf' in it.

Remember all the line that start with ';' is a comment.

if you want to redshift use the internet for your location install geoclue

sudo apt-get install geoclue-2.0