How to show file extensions in OS X

Step-by-step instructions

Method 1: Show the file extension of an individual file

  1. Right-click a file and select “Get Info” (⌘+I).
  2. Expand “Name & Extension” in the file information window.
  3. Uncheck the “Hide extension” checkbox.

Method 2: Show file extensions for all files

  1. Select “Preferences…” from the Finder menu.
  2. Choose “Advanced” and select the “Show all filename extensions” checkbox.