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FSCK(8) NetBSD System Manager's Manual FSCK(8)
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fsck -- file system consistency check and interactive repair
fsck [-dfnPpqvy] [-l maxparallel] [-T fstype:fsoptions] [-t fstype]
[-x mountpoint] [special | node ...]
The fsck command invokes file system-specific programs to check the spe-
cial devices listed in the fstab(5) file or in the command line for con-
It is normally used in the script /etc/rc during automatic reboot. If no
file systems are specified, and ``preen'' mode is enabled ( -p option)
fsck reads the table /etc/fstab to determine which file systems to check,
in what order. Only partitions in fstab that are mounted ``rw,'' ``rq''
or ``ro'' and that have non-zero pass number are checked. File systems
with pass number 1 (normally just the root file system) are checked one
at a time. When pass 1 completes, all remaining file systems are
checked, running one process per disk drive. By default, file systems
which are already mounted read-write are not checked. The disk drive
containing each file system is inferred from the longest prefix of the
device name that ends in a digit; the remaining characters are assumed to
be the partition designator.
The options are as follows:
-d Debugging mode. Just print the commands without executing them.
-f Force checking of file systems, even when they are marked clean
(for file systems that support this), or when they are mounted
Limit the number of parallel checks to the number specified in
the following argument. By default, the limit is the number of
disks, running one process per disk. If a smaller limit is
given, the disks are checked round-robin, one file system at a
-n Causes fsck to assume no as the answer to all operator questions,
-P Display a progress meter for each file system check. This option
also disables parallel checking. Note that progress meters are
not supported by all file system types.
-p Enter preen mode. In preen mode, fsck will check all file sys-
tems listed in /etc/fstab according to their pass number, and
will make minor repairs without human intervention.
-q Quiet mode, do not output any messages for clean file systems.
List of comma separated file system specific options for the
specified file system type, in the same format as mount(8).
Invoke fsck only for the comma separated list of file system
types. If the list starts with ``no'' then invoke fsck for the
file system types that are not specified in the list.
-v Print the commands before executing them.
Exclude the file system which has a mountpoint the same as in
/etc/fstab. Used only in ``preen'' mode.
-y Causes fsck to assume yes as the answer to all operator ques-
/etc/fstab file system table
fsck exits with 0 on success. Any major problems will cause fsck to exit
with the following non-zero exit(3) codes, so as to alert any invoking
program or script that human intervention is required.
1 Usage problem.
2 Unresolved errors while checking the file system. Re-running fsck
on the file system(s) is required.
4 The root file system was changed in the process of checking, and
updating the mount was unsuccessful. A reboot (without sync) is
8 The file system check has failed, and a subsequent check is
required that will require human intervention.
12 fsck exited because of the result of a signal (usually SIGINT or
SIGQUIT from the terminal).
fstab(5), fsck_ext2fs(8), fsck_ffs(8), fsck_lfs(8), fsck_msdos(8),
An fsck utility appeared in 4.0BSD. It was reimplemented as a file sys-
tem independent wrapper in NetBSD 1.3. The original file system specific
utility became fsck_ffs(8) at this point.
NetBSD 9.99 April 18, 2020 NetBSD 9.99