NAME

fsck_msdos — DOS/Windows (FAT) file system consistency check

SYNOPSIS

DESCRIPTION

The fsck_msdos utility verifies and repairs FAT file systems (more commonly known as DOS file systems).

The first form of fsck_msdos quickly checks the specified file systems to determine whether they were cleanly unmounted.

The second form of fsck_msdos preens the specified file systems. It is normally started by fsck(8) run from /etc/rc.boot during automatic reboot, when a FAT file system 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 third form of fsck_msdos checks the specified file systems and tries to repair all detected inconsistencies, requesting confirmation before making any changes. The default behavior is to always ask for confirmation of each change. Use the -n or -y options to override this default behavior.

The options are as follows:

-q

Causes fsck_msdos to quickly check whether the volume was unmounted cleanly. If the volume was unmounted cleanly, then the exit status is 0. If the volume was not unmounted cleanly, then the exit status will be non-zero. In either case, a message is printed to standard output describing whether the volume was clean or dirty.

-f

This option is ignored by fsck_msdos and is present only for compatibility with programs that check other file system types for consistency.

-n

Causes fsck_msdos to assume no as the answer to all operator questions, except “CONTINUE?”.

-p

Preen the specified file systems.

-y

Causes fsck_msdos to assume yes as the answer to all operator questions.

-M

Limits the amount of memory used by fsck_msdos.

-S directory

Causes fsck_msdos to create a shadow file containing all metadata read from the device in the given directory. This functionality is intended for inclusion with bug reports regarding excpetional problems. One file is created for each checked device. fsck_msdos may re-read metadata from disk at different phases of the repair process. If the repair process has repaired the metadata, the shadow file will capture its state as last read from disk. For optimal debug value, the shadow file should be captured in conjunction with the -n option. The shadow file's name will be shadow-diskXsY or shadow-fd<X>, depends on the information given to fsck_msdos. If this file already exists, fsck_msdos will attempt to add a counter postfix to the name. The resulting shadow file can be mounted by diskimagetool. Failure to generate or write to the shadow file will not affect the behavior of fsck_msdos.

EXIT VALUES

fsck_msdos exits with a value of 0 when the filesystem is clean (or has been repaired), and 8 otherwise.

SEE ALSO

fsck(8)