Select Startup Disk

The most common way to select the startup disk is using the "Startup Disk" preference pane. However, there are times when you want to do this using the command line.

$ sudo bless -mount /Volumes/MY_PARTITION -setBoot

Replace MY_PARTITION with the appropriate volume name, and reboot

Reformat a disk partition

To reformat a disk partition:

$ diskutil reformat /path/to/device

or

$ diskutil reformat /Volumes/[mount point]