OS X has lots of files you can’t see. This is to make it look prettier and also so you don’t break things. Sometimes you may want to see a hidden folder. For example there’s a Library folder which can contain settings for Applications. To show hidden files in OSX from the finder, click in a finder window and press “Shift Command .” (Shift – Command – Period).

It will look something like this when you can see the hidden files. All the slightly opaque files are hidden files.