gpart 0.3-0.ec03350 Guess and recover PC-style partition tables
Gpart tries to guess the partitions on a PC-style, MBR-partitioned disk after they have been inadvertently deleted or the primary partition table at sector 0 damaged. In both cases, the contents of these partitions still exist on the disk but the operating system cannot access them.
Gpart ignores the partition table and scans each sector of the device or image file for several known file system and partition types. Only partitions which have been formatted in some way can be recognized. Several file system guessing modules are built in; more can be written and loaded at run time.
The guessed table can be restored manually, for example with
fdisk, written to a file, or---if you firmly believe it's entirely correct---directly to disk.
It should be stressed that gpart does a very heuristic job. It can easily be right in its guesswork but it can also be terribly wrong. Never believe its output without any plausibility checks.