Discretionary control over file extensions

The Mac uses three-letter file extensions just like the PC, only it hides them by default. If you’ve moved from a PC to a Mac (welcome!) or just prefer to see the file extensions, the Mac will accommodate you. There are definitely times when having discretionary control over individual files is a boon and this tip will show you how.

Sure, you could go to Finder → Preferences → Advanced and turn on Show all file extensions if you wanted file extensions turned on globally. But what if you’d like to choose which individual files are allowed to show their extensions?

Pay attention the next time you save a file. The Save and Save As dialog in most (but not all) applications include a checkbox labeled either Hide Extension or Append File Extension. Just make sure you uncheck the former or check the latter to make that individual file display its file extension.