FSCK_HFS(8)

NAME
fsck_hfs - HFS file system consistency check

SYNOPSIS
fsck_hfs -q [-df] special ...
fsck_hfs -p [-df] special ...
fsck_hfs [-n | -y | -r] [-dfgl] [-m mode] [-c size] special ...

DESCRIPTION

The fsck_hfs utility verifies and repairs standard HFS and HFS+ file systems.

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

The second form of fsck_hfs preens the specified file systems. It is normally started by fsck(8) run from /etc/rc.boot during automatic reboot, when a HFS file system is detected. When preening file systems, fsck_hfs will fix common inconsistencies for file systems that were not unmounted cleanly. If more serious problems are found, fsck_hfs does not try to fix them, indicates that it was not successful, and exits.

The third form of fsck_hfs checks the specified file systems and tries to repair all detected inconsistencies.

If no options are specified fsck_hfs will always check and attempt to fix the specified file systems.

The options are as follows:

-c size
    Specify the size of the cache used by fsck_hfs internally. Bigger size can result in better performance but can result in deadlock when used with -l option. Size can be specified as a decimal, octal, or hexadecimal number. If the number ends with a ``k'', ``m'', or ``g'', the number is multiplied by 1024 (1K), 1048576 (1M), or 1073741824 (1G), respectively.

-d  Display debugging information. This option may provide useful information when fsck_hfs cannot repair a damaged file system.

-f  When used with the -p option, force fsck_hfs to check `clean' file systems, otherwise it means force fsck_hfs to check and repair journaled HFS+ file systems.

-g  Causes fsck_hfs to generate it's output strings in GUI format. This option is used when another application with a graphical user interface (like Mac OS X Disk Utility) is envoking the fsck_hfs tool.

-l  Lock down the file system and perform a test-only check. This makes it possible to check a file system that is currently mounted, although no repairs can be made.

-m mode
    Mode is an octal number that will be used to set the permissions for the lost+found directory when it is created. The lost+found directory is only created when a volume is repaired and orphaned files or directories are detected. fsck_hfs places orphaned files and directories into the lost+found directory (located at the root of the volume). The default mode is 01777.

-p  Preen the specified file systems.

-q  Causes fsck_hfs 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.

-y  Always attempt to repair any damage that is found.

-n  Never attempt to repair any damage that is found.

-r  Rebuild the catalog file on the specified file system. This option currently will only work if there is enough contiguous space on the specified file system for a new catalog file and if there is no damage to the leaf nodes in the existing catalog file.

Because of inconsistencies between the block device and the buffer cache, the raw device should always be used.

SEE ALSO
fsck(8)

BUGS
fsck_hfs is not able to fix some inconsistencies that it detects.

HISTORY
The fsck_hfs command appeared in Mac OS X Server 1.0 .