colorcheck

The colorcheck command can be used to test whether or not your terminal emulator properly supports 24-bit true color mode (16,777,216 colors). If this is not the case, pastel can only show 8-bit approximations (256 colors):

bash

pastel colorcheck

If everything works correctly, the output should look likes this (the background color and font colors may be different, but the color panels should look the same):

If you find it hard to compare the colors visually, you can also use a colorpicker (pastel pick) to make sure that the three colors in the 24-bit panels are (from left to right):

#492732, rgb(73, 39, 50)
#10331e, rgb(16, 51, 30)
#1d365a, rgb(29, 54, 90)