How to use the command redshift (with examples)

Redshift is a command-line tool that allows you to adjust the color temperature of your screen based on your surroundings. This can help reduce eye strain and improve sleep by reducing the amount of blue light emitted from the screen. Redshift uses your geographic coordinates and the time of day to determine the appropriate color temperature for your screen.

Use case 1: Turn on Redshift with 5700K temperature during day and 3600K at night

Code:

redshift -t 5700:3600

Motivation:

Using this example, you can configure Redshift to automatically adjust the color temperature of your screen based on the time of day. During the day, a higher color temperature of 5700K provides a cool, bluish tint to the screen, while at night, a lower color temperature of 3600K gives a warmer, orange-red tone. This mimics the natural sunlight during the day and artificial lighting during the night, which can help reduce eye strain and promote better sleep patterns.

Explanation:

• -t flag: Specifies the color temperature transition range. The first value (5700) represents the color temperature during the day, while the second value (3600) represents the color temperature at night. The transition between these two values happens gradually based on the time of day.

Example output:

Redshift will adjust the color temperature of your screen based on the specified values. During the day, the screen will have a cool tint with a color temperature of 5700K, and at night, it will transition to a warmer tint with a color temperature of 3600K.

Use case 2: Turn on Redshift with a manually specified custom location

Code:

redshift -l latitude:longitude

Motivation:

In some cases, Redshift might not accurately determine your geographic location, leading to incorrect color temperature adjustments. By using this example, you can manually specify your location’s latitude and longitude, ensuring that Redshift calculates the correct color temperature for your screen based on your actual surroundings.

Explanation:

• -l flag: Specifies the latitude and longitude of your location. The latitude value represents your position relative to the Earth’s equator, while the longitude value represents your position relative to the prime meridian.

Example output:

Redshift will adjust the color temperature of your screen based on the manually specified location. This ensures that the color temperature is accurately determined, leading to better eye comfort and sleep quality.

Use case 3: Turn on Redshift with 70% screen brightness during the day and 40% brightness at night

Code:

redshift -b 0.7:0.4

Motivation:

Adjusting the brightness of your screen can further enhance visual comfort, especially when using Redshift to reduce eye strain during different times of day. By using this example, you can set the desired screen brightness levels during the day and night to complement the color temperature adjustments made by Redshift.

Explanation:

• -b flag: Specifies the screen brightness transition range. The first value (0.7) represents the screen brightness during the day, while the second value (0.4) represents the screen brightness at night. The screen brightness will transition smoothly between these two values based on the time of day.

Example output:

Redshift will adjust the color temperature and screen brightness of your screen based on the specified values. During the day, the screen will have a higher brightness level of 70%, and at night, it will transition to a lower brightness level of 40%.

Use case 4: Turn on Redshift with custom gamma levels

Code:

redshift -g red:green:blue

Motivation:

Gamma correction can be useful for fine-tuning the color balance of your screen. By adjusting the gamma levels, you can modify the intensity of each color channel (red, green, and blue) to achieve more accurate and pleasing visual results. This example allows you to specify custom gamma levels to suit your preferences.

Explanation:

• -g flag: Specifies the custom gamma levels for the red, green, and blue color channels. The values should be between 0 and 1, where 0 represents complete absence of the color channel, and 1 represents the maximum intensity of the color channel.

Example output:

Redshift will adjust the color temperature of your screen based on the specified values. You will observe the customized intensity of each color channel, resulting in a screen display that aligns with your personal preferences.

Use case 5: Turn on Redshift with a constant unchanging color temperature

Code:

redshift -O temperature

Motivation:

While Redshift typically adjusts the color temperature of your screen based on the time of day, you may prefer a constant color temperature setting. This example allows you to set a fixed color temperature that does not change throughout the day, providing consistent visual comfort.

Explanation:

• -O flag: Specifies a constant color temperature value. The “temperature” parameter should be replaced with the desired color temperature value, such as 5500K or 6500K.

Example output:

Redshift will set the color temperature of your screen to the specified value, regardless of the time of day. This will result in a consistent color temperature setting that remains unchanged.

Conclusion:

Redshift is a powerful command-line tool that helps reduce eye strain and improve sleep quality by adjusting the color temperature of your screen. By using different combinations of command-line arguments, you can customize Redshift to suit your preferences, location, and screen brightness requirements. Experimenting with the provided use cases can help you find the optimal configuration for your visual comfort and well-being.