fsck - check and repair file systems
fsck [-F FSType] [-m] [-V] [-v] [special]...
fsck [-F FSType] [-n | N | y | Y] [-V] [-v]
[-o FSType-specific-options] [special]...
fsck audits and interactively repairs inconsistent file system
conditions. If the file system is inconsistent the default action for each
correction is to wait for the user to respond yes or no. If the
user does not have write permission fsck defaults to a no
action. Some corrective actions will result in loss of data. The amount and
severity of data loss can be determined from the diagnostic output.
FSType-specific-options are options specified in a
comma-separated (with no intervening spaces) list of options or
keyword-attribute pairs for interpretation by the FSType-specific
module of the command.
special represents the character special device on which
the file system resides, for example, /dev/rdsk/c1t0d0s7. Note: the
character special device, not the block special device, should be used.
fsck will not work if the block device is mounted.
If no special device is specified fsck checks the
file systems listed in /etc/vfstab. Those entries in
/etc/vfstab which have a character special device entry in the
fsckdev field and have a non-zero numeric entry in the
fsckpass field will be checked. Specifying -F FSType
limits the file systems to be checked to those of the type indicated.
If special is specified, but -F is not, the file
system type will be determined by looking for a matching entry in
/etc/vfstab. If no entry is found, the default local file system type
specified in /etc/default/fs will be used.
If a file system type supports parallel checking, for example,
ufs, some file systems eligible for checking may be checked in
parallel. Consult the file system-specific man page (for example,
fsck_ufs(8)) for more information.
The following generic options are supported:
Specify the file system type on which to operate.
Check but do not repair. This option checks that the file
system is suitable for mounting, returning the appropriate exit status. If the
file system is ready for mounting, fsck
displays a message such as:
ufs fsck: sanity check: /dev/rdsk/c0t3d0s1 okay
-n | -N
Assume a no response to all questions asked by
fsck; do not open the file system for writing.
Echo the expanded command line but do not execute the
command. This option may be used to verify and to validate the command
Enables verbose output. Might not be supported by all
filesystem-specific fsck implementations.
-y | Y
Assume a yes response to all questions asked by
can be any combination of
the following separated by commas (with no intervening spaces).
Use block n
as the super block for the file
system. Block 32 is always one of the alternate super blocks. Determine the
location of other super blocks by running newfs(8)
with the -Nv
If the file system is in the old (static table) format,
convert it to the new (dynamic table) format. If the file system is in the new
format, convert it to the old format provided the old format can support the
file system configuration. In interactive mode, fsck
will list the
direction the conversion is to be made and ask whether the conversion should
be done. If a negative answer is given, no further operations are done on the
file system. In preen mode, the direction of the conversion is listed and done
if possible without user interaction. Conversion in preen mode is best used
when all the file systems are being converted at once. The format of a file
system can be determined from the first line of output from fstyp(8)
Note: the c
option is seldom used and is included only for
compatibility with pre-4.1 releases. There is no guarantee that this option
will be included in future releases.
Force checking of file systems regardless of the state of
their super block clean flag.
Check and fix the file system non-interactively
("preen"). Exit immediately if there is a problem requiring
intervention. This option is required to enable parallel file system
Check writable file systems only.
file system is unmounted and OK
erroneous parameters are specified
file system is unmounted and needs checking (fsck
file system is already mounted
cannot stat device
a filesystem that is mounted read/write was modified -
uncorrectable errors detected - terminate normally
a signal was caught during processing
uncorrectable errors detected - terminate
file system is mounted read-only and is OK
The fsck command is large file aware for UFS file systems, per the
largefile(7) man page.
default local file system type. Default values can be set
for the following flags in /etc/default/fs
. For example:
The default partition for a command if no FSType is
list of default parameters for each file system
See attributes(7) for descriptions of the following attributes:
ufs(4FS), vfstab(5), attributes(7), largefile(7),
clri(8), fsck_ufs(8), fsdb_ufs(8), fsirand(8),
fstyp(8), mkfs(8), mkfs_ufs(8), mountall(8),
The operating system buffers file system data. Running fsck on a mounted
file system can cause the operating system's buffers to become out of date
with respect to the disk. For this reason, the file system should be
unmounted when fsck is used. If this is not possible, care
should be taken that the system is quiescent and that it is rebooted
immediately after fsck is run. Quite often, however, this will not be
sufficient. A panic will probably occur if running fsck on a file
system modifies the file system.
This command may not be supported for all FSTypes.
Starting with Solaris 9, fsck manages extended attribute
data on the disk. (See fsattr(7) for a description of extended file
attributes.) A file system with extended attributes can be mounted on
versions of Solaris that are not attribute-aware (versions prior to Solaris
9), but the attributes will not be accessible and fsck will strip
them from the files and place them in lost+found. Once the attributes
have been stripped, the file system is completely stable on versions of
Solaris that are not attribute-aware, but would be considered corrupted on
attribute-aware versions. In the latter circumstance, run the
attribute-aware fsck to stabilize the file system before using it in
an attribute-aware environment.