GPT fdisk (consisting of the gdisk, cgdisk, sgdisk, and fixparts programs)
is a set of text-mode partitioning tools for Linux, FreeBSD, Mac OS X,
and Windows.
The gdisk, cgdisk, and sgdisk programs work on Globally Unique Identifier
(GUID) Partition Table (GPT) disks, rather than on the older (and once more
common) Master Boot Record (MBR) partition tables.
The fixparts program repairs certain types of damage to MBR disks and
enables changing partition types from primary to logical and vice-versa.
You can learn more about fixparts on its dedicated Web page.