Show Hidden Files 10.9 and lower

First Open Terminal (Applications\Utilities)

To show hidden files, Type this command and then press enter:

defaults write com.apple.finder AppleShowAllFiles TRUE

To allow the files to be shown, you must restart Finder. You can do this by holding the Option key, click and hold the Finder icon. When the context menu shows, select Relaunch.

Finder will now restart.

Now all hidden files are showing!

To hide files again, type:

defaults write com.apple.finder AppleShowAllFiles FALSE

You can also restart finder by using the following command from the terminal:

killall Finder