Updating boot caches os x
These can be used either if you are logged in in Single User mode (after holding Command-S at startup to drop you to a root terminal prompt instead of loading the OS X interface), or if you are logged in remotely through an SSH connection.
Keep in mind that clearing the system cache can cause your Mac to freeze or crash unexpectedly; this is a normal response to clearing the cache. If you see an option that says "Develop," click on it.
Therefore, be sure to run "disktuil list" again before running the command to find out the proper ID to use.
Apple has offered a Safe Boot (sometimes called Safe Mode) option ever since Jaguar (OS X 10.2.x).
Since OS X systems generally have an EFI boot partition, this usually offsets the boot drive's slice number to be disk0s2.
The third option is to simply target the root of the boot filesystem using a single forward-slash character.