After playing around with redshift I managed to build some scripts for it in Linux. As it does not have ANY Gui and the location thing is dependent on where you are you have to mess around with it to get it to work. Also it seems as though there is a bug where it inverts the gps locations but you simply switch the brightness level around and its the same thing.
Alright install the Redlight as per instructions.
Then right click create file and edit with gedit.
Paste the following code in:
#!/bin/bash
gtk-redshift -l 43.39:79.23 -t 4600:5600 -g 0.8 -m vidmode -v
-l stands for lat long, google your location. xx.xx:xx.xx = lat:long
-t stands for brightness levels, i dint like the default 3600 but 4600 is good for my eyes. I had to invert it for it to work properly as for some reason Redlight thinks my location is during the day at night and vice versa. Mess around with it until you like the results.
Anyway save it. Right click and edit file Properties, go to Permissions and check-box Allow executing file as program.
Then simply dble click and your good!
If you want to autostart it in ubuntu then go to System>Preference> Startup Applications and drag the script in. Should work.
Happy night-surfing