It’s been a lot of years since colors were first introduced on the command line of Unix/Linux systems. But, yes, there was a time when terminal windows were simply black and white. Today, file names might show up in a number of different shades — green, red, blue, purple/magenta, or some other color — depending on the type of file (whether they are executable files, directories, images, etc.) or the file extensions. Sometimes you might just want to turn the colors off because they’re distracting you from what you want to pay attention to. At other times, they help you to instantly identify important file characteristics. In any case, there’s a lot that you can do to control the colors that are used and what they’re used for.