Updating a computer os without an internet connection
For that reason, OS X includes an easy-to-use software update mechanism that automatically checks the Apple servers via the Internet to make sure you’re running the latest Apple-sourced software.
Automatic software update checking is enabled by default as soon as you start using your Mac.
Adding new capabilities is the very reason “software” exists.
On the other hand, by default, most OS X system and Mac App Store updates are automatically downloaded in the background but not installed.
In this case, when updates are ready to be installed, a Mac App Store notification displays, stating “Updates Available.” From this notification you can click Install or Restart, which will immediately install the updates and restart the computer if necessary.
If the update items have already been downloaded, a notification displays.
In either case, when you select a restart option, the system verifies the downloaded updates, logs out the current user, installs the updates, restarts the system, and then automatically logs back in to the user account that initiated the updates.