How to create a command to incrementally increase redshift's color temperature?

redshift is a package that enables blue light filter, so people can avoid eye strain. This software is pretty good, but it lacks controls to adjust the filter color temperature, **incrementally**: no sliders, buttons or commands. When I say "incrementally", what I mean is that I need a command to set color temperature according to the previous value. The package xbacklight has a good example: xbacklight +10 #increases monitor brightness by 10% or... xbacklight -10 #decreases monitor brightness by 10% Hence, if brightness value was 70%: now, it would become 60%. What I need is a command like this: temperature +10 #increases color temperature by 10% --- ### what redshift already provides With redshift, you can manually set color temperature like this: redshift -O 3000K Although, there's no built-in way to increase this value by 10%. Therefore, if you need to increase the value, you need to do this: redshift -x #reset the previous value redshift -O 3300K Notice that: not only I had to calculate the new value manually, I also had to reset the previous value, first. --- ### why do I need to do this I study all day, using my laptop. So, I need to have blue light filter on, in order to save my eyes and be more productive. I have some some ideas on how to make a simple shell script that could do this, but I have no idea how I would go and store the previous value variable or where to store this kinda script properly.