The partition table is where you tell the computer how many partitions you want to break the drive into, and how big each one is. This is the partition that will be loaded when the computer starts up. Which is Reboot, Backup. Now you have a bootable rescue disk you can use to restore the original partition table in an emergency. The command line options allow you to disable specific steps of the Reboot process.
Commands can be in either upper or lower case, and are preceeded with a dash.
Partition tables aren't filled in order. Figure out which partition you wanted to make active, and make it so. Attempt to detect disk caching, and attempt to cause any disk caches to be written out. Will attempt to reboot the computer. Option Function -Q Quiet mode.