fsck_hfs - HFS file system consistency check
fsck_hfs -q [-df] special ...
fsck_hfs -p [-df] special ...
fsck_hfs [-n | -y | -r] [-dfgl] [-m mode] [-c size] special ...
The fsck_hfs utility verifies and repairs standard HFS and HFS+ file
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
-d Display debugging information. This option may provide
useful information when fsck_hfs cannot repair a damaged
-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
invoking 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.
fsck_hfs is not able to fix some inconsistencies that it detects.
The fsck_hfs command appeared in Mac OS X Server 1.0 .