FSCK(8) | System Manager's Manual | FSCK(8)

# NAME

`fsck` — file system consistency check and interactive repair

# SYNOPSIS

`fsck` | [`-dfnPpqvy`] [`-l` maxparallel] [`-T` fstype:fsoptions] [`-t` fstype] [`-x` mountpoint] [special | node ...]

# DESCRIPTION

The `fsck` command invokes file system-specific programs to check the special devices listed in the fstab(5) file or in the command line for consistency.

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 read-write.
`-l` maxparallel
  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 time.
`-n`
  Causes `fsck` to assume no as the answer to all operator questions, except "CONTINUE?".
`-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 systems 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.
`-T` fstype:fsoptions
  List of comma separated file system specific options for the specified file system type, in the same format as mount(8).
`-t` fstype
  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.
`-x` mountpoint
  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 questions.

# FILES

/etc/fstab
  file system table

# EXIT STATUS

`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 required.
`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).

# SEE ALSO

fstab(5), fsck_ext2fs(8), fsck_ffs(8), fsck_lfs(8), fsck_msdos(8), mount(8)

# HISTORY

An `fsck` utility appeared in 4.0BSD. It was reimplemented as a file system independent wrapper in NetBSD 1.3. The original file system specific utility became fsck_ffs(8) at this point.

April 18, 2020 | NetBSD 11.0