You might suffer from eye strain if your job involves working on a computer for long hours. This is especially true if you stare at the computer monitor sitting in a dimly lit room.

One of the best ways of reducing computer eye strain is to change the colour of your monitor in relation to the time at your place.

For example, if you are sitting in a dimly lit room, working late at night, you can adjust the colour of your computer monitor to a less bright value. And during day time, when the windows are open and sunlight is streaming into the room, the brightness level of your monitor can be increased appropriately.

Fortunately, you don’t have to do all this manually.

You can use a specialized software to control and adjust the brightness level of your computer monitor. One such software is redshift.

Redshift is a command line tool that monitors and controls the computer monitor brightness levels according to predefined values.

Redshift runs on Windows, Linux, BSDs, and OS X. If you are using any main stream Linux distribution like Fedora, Ubuntu, Debian, or Arch Linux, you will find Redshift in their respective repositories.

For example, I used the following command to install Redshift in Fedora 16 -

$ su -c 'yum install redshift'

Redshift Usage

This is the most common syntax for using redshift -

redshift -l Latitude:Longitude -t day:night

Where, -l option denotes your current location which is provided as latitude and longitude.

-t option is used to set the colour temperature during daytime and night. The value 6500 is the median. Any value above 6500 will give a bluish tint and any value below 6500 will give a reddish tint to your monitor. Initially you will have to make minor adjustments to the values in the -t option to get the desired hue to your liking.

So for example, if you live in New York then you can run redshift with the following options

$ redshift -l 40.47:73.58 -t 6500:5500

Where latitude is 40 47N and longitude is 73 58E for New York.

If you are living in India, you can use the following resource to find out the correct latitude and longitude of your place.

Later you can set-up redshift to run automatically during start-up.