fsck_msdos —
DOS/Windows (FAT) filesystem consistency checker
  
    | fsck_msdos | -p[-f]
      filesystem ... | 
  
    | fsck_msdos | [ -fny] [-xsnap-backup] filesystem
      ... | 
The fsck_msdos utility verifies and repairs FAT
  filesystems (more commonly known as DOS filesystems).
The first form of fsck_msdos preens the
    specified filesystems. It is normally started by
    fsck(8) run from
    /etc/rc during automatic reboot, when a FAT
    filesystem is detected. When preening file systems,
    fsck_msdos will fix common inconsistencies
    non-interactively. If more serious problems are found,
    fsck_msdos does not try to fix them, indicates that
    it was not successful, and exits.
The second form of fsck_msdos checks the
    specified file systems and tries to repair all detected inconsistencies,
    requesting confirmation before making any changes.
The options are as follows:
  - -f
- This option is ignored by fsck_msdos, and is
      present only for compatibility with programs that check other file system
      types for consistency, such as
      fsck_ffs(8).
- -n
- Causes fsck_msdosto assume no as the answer to
      all operator questions, except “CONTINUE?”.
- -p
- Preen the specified filesystems.
- -xsnap-backup
- Use a snapshot with snap-backup as backup to check a
      read-write mounted filesystem. Must be used with
      -n. See
      fss(4) for more details. The
      point is to check an internally-consistent version of the filesystem to
      find out if it is damaged; on failure one should unmount the filesystem
      and repair it.
- -y
- Causes fsck_msdosto assume yes as the answer to
      all operator questions.
Afsck_msdos utility appeared in NetBSD
  1.2.
fsck_msdos is still under construction.