The fsck_msdosfs utility verifies and repairs FAT file systems (more commonly known as DOS file systems).
The first form of fsck_msdosfs preens the specified file systems. It is normally started by fsck(8) run from /etc/rc during automatic reboot, when a FAT file system is detected. When preening file systems, fsck_msdosfs will fix common inconsistencies non-interactively. If more serious problems are found, fsck_msdosfs does not try to fix them, indicates that it was not successful, and exits.
The second form of fsck_msdosfs checks the specified file systems and tries to repair all detected inconsistencies, requesting confirmation before making any changes.
The options are as follows: