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

NAME
     fsck - file system consistency check and interactive repair

SYNOPSIS
     fsck [-Cdfnpvy] [-B | -F] [-T fstype:fsoptions] [-t fstype]
          [special | node] ...

DESCRIPTION
     The fsck utility 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.
     Traditionally, fsck is invoked before the file systems are mounted and
     all checks are done to completion at that time.  If background checking
     is available, fsck is invoked twice.  It is first invoked at the
     traditional time, before the file systems are mounted, with the -F flag
     to do checking on all the file systems that cannot do background
     checking.  It is then invoked a second time, after the system has
     completed going multiuser, with the -B flag to do checking on all the
     file systems that can do background checking.  Unlike the foreground
     checking, the background checking is started asynchronously so that other
     system activity can proceed even on the file systems that are being
     checked.

     If no file systems are specified, fsck reads the table /etc/fstab to
     determine which file systems to check.  Only partitions in /etc/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 always checked one at a time.

     If not in preen mode, the remaining entries are checked in order of
     increasing pass number one at a time.  This is needed when interaction
     with fsck is required.

     In preen mode, after pass 1 completes, all remaining file systems are
     checked, in pass number order running one process per disk drive in
     parallel for each pass number in increasing order.

     In other words: In preen mode all pass 1 partitions are checked
     sequentially.  Next all pass 2 partitions are checked in parallel, one
     process per disk drive.  Next all pass 3 partitions are checked in
     parallel, one process per disk drive.  etc.

     The disk drive containing each file system is inferred from the shortest
     prefix of the device name that ends in a digit; the remaining characters
     are assumed to be the partition and slice designators.

     The options are as follows:

     -C      Check if the ``clean'' flag is set in the superblock and skip
             file system checks if file system was properly dismounted and
             marked clean.

     -d      Debugging mode.  Just print the commands without executing them.
             Available only if fsck is compiled to support it.

     -f      Force checking of file systems, even when they are marked clean
             (for file systems that support this).

     -n      Causes fsck to assume no as the answer to all operator questions,
             except "CONTINUE?".

     -p      Enter preen mode.  In preen mode, only a restricted class of
             innocuous file system inconsistencies will be corrected.  If
             unexpected inconsistencies caused by hardware or software
             failures are encountered, the check program will exit with a
             failure.  See the manual pages for the individual check programs
             for a list of the sorts of failures that they correct when
             running in preen mode.

     -F      Run in foreground mode.  The check program for each file system
             is invoked with the -F flag to determine whether it wishes to run
             as part of the boot up sequence, or if it is able to do its job
             in background after the system is up and running.  A non-zero
             exit code indicates that it wants to run in foreground and the
             check program is invoked.  A zero exit code indicates that it is
             able to run later in background and just a deferred message is
             printed.

     -B      Run in background mode.  The check program for each file system
             is invoked with the -F flag to determine whether it wishes to run
             as part of the boot up sequence, or if it is able to do its job
             in background after the system is up and running.  A non-zero
             exit code indicates that it wanted to run in foreground which is
             assumed to have been done, so the file system is skipped.  A zero
             exit code indicates that it is able to run in background so the
             check program is invoked with the -B flag to indicate that a
             check on the active file system should be done.  When running in
             background mode, only one file system at a time will be checked.
             Note that background fsck is limited to checking for only the
             most commonly occurring file system abnormalities.  Under certain
             circumstances, some errors can escape background fsck.  It is
             recommended that you perform foreground fsck on your systems
             periodically and whenever you encounter file-system-related
             panics.

     -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.

     -y      Causes fsck to assume yes as the answer to all operator
             questions.

     -T fstype:fsoptions
             List of comma separated file system specific options for the
             specified file system type, in the same format as mount(8).

FILES
     /etc/fstab  file system table

SEE ALSO
     fstab(5), fsck_ffs(8), fsck_msdosfs(8), mount(8)

FreeBSD 11.0-PRERELEASE        January 25, 2009        FreeBSD 11.0-PRERELEASE

NAME | SYNOPSIS | DESCRIPTION | FILES | SEE ALSO

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