

The last step is to use Terminal to hide the special system files that shouldn't normally be visible. The Packages folder contains a series of packages. So far, we've created a bootable USB flash drive that contains just enough of a system to allow your Mac to boot.

Before proceeding, make a backup of the data on the flash drive, if any.

The next series of steps will erase all data on the USB flash drive. How to install a fresh copy of OS X on your Mac | iMore!.
