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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] [-c fstab]
	  [special | node] ...

DESCRIPTION
     The fsck utility invokes file system-specific programs to check the spe-
     cial devices listed in the	fstab(5) file or in the	command	line for con-
     sistency.

     It	is normally used in the	script /etc/rc during automatic	reboot.	 Tra-
     ditionally, 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 check-
     ing on all	the file systems that cannot do	background checking.  It is
     then invoked a second time, after the system has completed	going multi-
     user, 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 pro-
     ceed 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 par-
     allel for each pass number	in increasing order.

     In	other words: In	preen mode all pass 1 partitions are checked sequen-
     tially.  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.

     -c	fstab
	     Specify the fstab file to use.

     -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 fail-
	     ures 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 pan-
	     ics.

     -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 ques-
	     tions.

     -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	10.1		       January 25, 2009			  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | FILES | SEE ALSO

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