Setting your Mac to view file extensions

What are file extensions?

File extensions are the end part of file names. For example the file index.html has a file extension of .html

• Extensions indicate the type of file.
• Examples of extensions:
  • web page: .html or .htm (note that both will work, but it's best to use one of the other in your file names for consistency)
  • web image file: .gif or .jpg/.jpeg (either one works)
  • Flash file (.swf, .flv)
  • When you see a file's extension, it enables you to identify the file by its file type without needing to open that file.
• Note: that renaming a file and including a file extension that is not correct for the type of data in the file will not succeed in changing the inherent properties of the file. Such a renamed file will not work properly.

It is preferable to see file extensions

• By default, Macs do not display file extensions.
• However, if you can see file extensions, you can rapidly determine the type of file, without needing to open it.
• After you follow the steps below you will be able to see extensions in your Finder and in file browsers. File browsers are the dialog boxes that appear when, for example, you select File -> Open.
• You will now set you Mac to make file extensions visible.

Please do the following:

1. Go to the Finder's Preferences.
   1. If you don't know how to get to the Finder, hold down the Apple button and tap on the Tab key until you select the blue smiley Finder icon:
          
   2. Then let go of the keys, this ought to set you to the Finder.
2. Enable Show all file extensions.
   
   

That's it!

© 2014 Dan Hitchcock Vaughan and licensors