Redshift adjusts the color temperature of your screen according to your surroundings. This may help your eyes hurt less if you are working in front of the screen at night.
$ redshift
Trying location provider `corelocation'...
Using provider `corelocation'.
Using method `quartz'.
Waiting for initial location to become available...
Waiting for authorization to obtain location...
Error obtaining location from CoreLocation: The operation couldn’t be completed. (kCLErrorDomain error 1.)
Unable to get location from provider.
brew install redshift
then
$ redshift
and i get this error: