An Introduction to File Extensions
In an effort to be “user-friendly,” Windows (and perhaps some other operating systems) hides the most important part of a file name from new computer users: the extension. Okay - we’re assuming that the reasoning behind hiding extensions is a “user-friendly” one because we just can’t come up with any other reason for hiding them. No harm could ever come from seeing an extension, but plenty could be learned from it. Fortunately you have this article to guide you through some of the most common extensions that you’ll run into.
But before you can see file extensions, you need to turn them on. From Windows Explorer, click on the “Tools” menu, and select “File Options.” Click the “View” tab and then uncheck the box next to “Hide file extensions for known file types.” Click “OK” and you’ll notice that the files in Windows Explorer show a dot and group of three letters after their names. That dot and group of three letters is known as an “extension,” and the extension explains what kind of file it is.
