Show File Name Extensions in Mac OS X
File extensions (like .jpg, .txt, .pdf, etc) make it easy to see what a specific file type format is, but as many Mac users notice, those file extensions are hidden by default in Mac OS X. While hiding the format suffix makes for a cleaner user experience and is fine for many users, it can be frustrating if you’d rather know instantly what file format type a file is just by looking at the name, and for many power users it’s one of the first things changed when setting up a Mac.
As we’ll demonstrate, Mac OS offers two choices for displaying file format extensions after file names: You can either set all extensions to be displayed for every file in Finder through a universal setting, or you can set extensions to be shown on a per file basis with the help of the Get Info command. For either choice, the file format type will be shown as part of the file name, changing something like “File” to display as “File.txt”.