Provided by: util-linux_2.19.1-2ubuntu3_i386 bug

NAME

       fsck - check and repair a Linux file system

SYNOPSIS

       fsck  [-lsAVRTMNP]  [-C  [fd]]  [-t  fstype]  [filesys...]   [--]  [fs-
       specific-options]

DESCRIPTION

       fsck is used to check and optionally repair  one  or  more  Linux  file
       systems.   filesys can be a device name (e.g.  /dev/hdc1, /dev/sdb2), a
       mount point (e.g.  /, /usr, /home), or an ext2 label or UUID  specifier
       (e.g.     UUID=8868abf6-88c5-4a83-98b8-bfc24057f7bd   or   LABEL=root).
       Normally, the fsck program will try to handle filesystems on  different
       physical  disk  drives  in  parallel to reduce the total amount of time
       needed to check all of the filesystems.

       If no filesystems are specified on the command line, and the -A  option
       is  not  specified,  fsck  will  default  to  checking  filesystems  in
       /etc/fstab serially.  This is equivalent to the -As options.

       The exit code returned by fsck is the sum of the following conditions:
            0    - No errors
            1    - File system errors corrected
            2    - System should be rebooted
            4    - File system errors left uncorrected
            8    - Operational error
            16   - Usage or syntax error
            32   - Fsck canceled by user request
            128  - Shared library error
       The exit code returned when multiple file systems are  checked  is  the
       bit-wise OR of the exit codes for each file system that is checked.

       In  actuality,  fsck  is simply a front-end for the various file system
       checkers (fsck.fstype) available under Linux.  The file system-specific
       checker  is  searched for in /sbin first, then in /etc/fs and /etc, and
       finally in the directories listed in  the  PATH  environment  variable.
       Please  see  the  file system-specific checker manual pages for further
       details.

OPTIONS

       -l     Lock whole-disk device by exclusive flock(2).  This  option  can
              be  used  with  one  device  only  (e.g.  -A and -l are mutually
              exclusive). This  option  is  recommended  when  more  fsck  (8)
              instances  are  executed in the same time. The option is ignored
              when used for multiple devices or  for  non-rotating  disk.  The
              fsck  does  not  lock  underlying  devices  if executed to check
              stacked  devices  (e.g.  MD  or  DM)  --  this  feature  is  not
              implemented yet.

       -s     Serialize  fsck  operations.   This  is  a  good idea if you are
              checking  multiple  filesystems  and  the  checkers  are  in  an
              interactive  mode.  (Note: e2fsck(8) runs in an interactive mode
              by default.  To make e2fsck(8) run in  a  non-interactive  mode,
              you  must  either  specify  the -p or -a option, if you wish for
              errors to be corrected automatically, or the -n option if you do
              not.)

       -t fslist
              Specifies the type(s) of file system to be checked.  When the -A
              flag is  specified,  only  filesystems  that  match  fslist  are
              checked.   The  fslist  parameter  is  a comma-separated list of
              filesystems and options specifiers.  All of the  filesystems  in
              this comma-separated list may be prefixed by a negation operator
              'no' or '!', which requests  that  only  those  filesystems  not
              listed  in fslist will be checked.  If all of the filesystems in
              fslist are not prefixed by a negation operator, then only  those
              filesystems listed in fslist will be checked.

              Options  specifiers  may  be  included  in  the  comma-separated
              fslist.  They  must  have  the  format  opts=fs-option.   If  an
              options  specifier  is  present,  then  only  filesystems  which
              contain fs-option in their mount  options  field  of  /etc/fstab
              will  be  checked.   If  the  options specifier is prefixed by a
              negation operator, then only those filesystems that do not  have
              fs-option  in  their  mount  options field of /etc/fstab will be
              checked.

              For example, if opts=ro appears in fslist, then only filesystems
              listed in /etc/fstab with the ro option will be checked.

              For compatibility with Mandrake distributions whose boot scripts
              depend upon an unauthorized UI change to the fsck program, if  a
              filesystem  type of loop is found in fslist, it is treated as if
              opts=loop were specified as an argument to the -t option.

              Normally, the  filesystem  type  is  deduced  by  searching  for
              filesys  in  the  /etc/fstab  file  and  using the corresponding
              entry.  If the type can not be deduced,  and  there  is  only  a
              single  filesystem  given  as an argument to the -t option, fsck
              will use the specified filesystem type.  If  this  type  is  not
              available, then the default file system type (currently ext2) is
              used.

       -A     Walk through the /etc/fstab file  and  try  to  check  all  file
              systems  in  one  run.   This  option is typically used from the
              /etc/rc system initialization file, instead of multiple commands
              for checking a single file system.

              The  root  filesystem will be checked first unless the -P option
              is specified (see  below).   After  that,  filesystems  will  be
              checked  in  the  order  specified  by the fs_passno (the sixth)
              field in the /etc/fstab  file.   Filesystems  with  a  fs_passno
              value  of 0 are skipped and are not checked at all.  Filesystems
              with a fs_passno value of greater than zero will be  checked  in
              order,  with  filesystems with the lowest fs_passno number being
              checked first.  If there are multiple filesystems with the  same
              pass  number,  fsck  will  attempt  to  check  them in parallel,
              although it will avoid running multiple filesystem checks on the
              same physical disk.

              fsck  does  not  check stacked devices (RAIDs, dm-crypt, ...) in
              parallel   with   any    other    device.    See    below    for
              FSCK_FORCE_ALL_PARALLEL  setting. The /sys filesystem is used to
              detemine dependencies between devices.

              Hence, a very common configuration in /etc/fstab files is to set
              the  root  filesystem  to have a fs_passno value of 1 and to set
              all other filesystems to have a fs_passno value of 2.  This will
              allow  fsck to automatically run filesystem checkers in parallel
              if it is advantageous to do  so.   System  administrators  might
              choose  not  to  use  this  configuration  if they need to avoid
              multiple filesystem checks running in parallel for  some  reason
              ---  for  example, if the machine in question is short on memory
              so that excessive paging is a concern.

              fsck normally does not check whether the device actually  exists
              before  calling  a  file system specific checker. Therefore non-
              existing devices may cause  the  system  to  enter  file  system
              repair  mode  during  boot  if  the  filesystem specific checker
              returns a fatal error. The /etc/fstab mount option nofail may be
              used  to  have  fsck skip non-existing devices.  fsck also skips
              non-existing devices that have the special file system type auto

       -C [  fd  ]
              Display completion/progress bars for those  filesystem  checkers
              (currently  only  for  ext2 and ext3) which support them.   Fsck
              will manage the filesystem checkers so that  only  one  of  them
              will  display  a  progress  bar  at  a time.  GUI front-ends may
              specify a file descriptor fd, in which  case  the  progress  bar
              information will be sent to that file descriptor.

       -M     Do  not  check  mounted filesystems and return an exit code of 0
              for mounted filesystems.

       -N     Don't execute, just show what would be done.

       -P     When the -A flag is set, check the root filesystem  in  parallel
              with the other filesystems.  This is not the safest thing in the
              world to do, since if the root filesystem  is  in  doubt  things
              like  the  e2fsck(8) executable might be corrupted!  This option
              is mainly  provided  for  those  sysadmins  who  don't  want  to
              repartition  the  root filesystem to be small and compact (which
              is really the right solution).

       -R     When checking all file systems with the -A flag, skip  the  root
              file system (in case it's already mounted read-write).

       -T     Don't show the title on startup.

       -V     Produce  verbose  output,  including  all  file  system-specific
              commands that are executed.

       fs-specific-options
              Options which are not understood  by  fsck  are  passed  to  the
              filesystem-specific  checker.   These  arguments  must  not take
              arguments, as there is no way for fsck to be  able  to  properly
              guess which arguments take options and which don't.

              Options  and  arguments  which follow the -- are treated as file
              system-specific options to be passed to the file system-specific
              checker.

              Please  note  that  fsck  is  not  designed  to pass arbitrarily
              complicated options to filesystem-specific checkers.  If  you're
              doing something complicated, please just execute the filesystem-
              specific checker directly.   If  you  pass  fsck  some  horribly
              complicated  option  and  arguments,  and it doesn't do what you
              expect, don't bother reporting  it  as  a  bug.   You're  almost
              certainly doing something that you shouldn't be doing with fsck.

       Options  to  different filesystem-specific fsck's are not standardized.
       If in doubt, please consult the man pages  of  the  filesystem-specific
       checker.   Although not guaranteed, the following options are supported
       by most file system checkers:

       -a     Automatically repair the file system without any questions  (use
              this  option with caution).  Note that e2fsck(8) supports -a for
              backwards compatibility only.  This option is mapped to e2fsck's
              -p  option  which is safe to use, unlike the -a option that some
              file system checkers support.

       -n     For some filesystem-specific checkers, the -n option will  cause
              the fs-specific fsck to avoid attempting to repair any problems,
              but simply report such problems to stdout.  This is however  not
              true  for  all  filesystem-specific  checkers.   In  particular,
              fsck.reiserfs(8) will not report any corruption  if  given  this
              option.  fsck.minix(8) does not support the -n option at all.

       -r     Interactively  repair  the  filesystem  (ask for confirmations).
              Note: It is generally a bad idea to use this option if  multiple
              fsck's  are  being  run  in  parallel.   Also  note that this is
              e2fsck's default behavior; it supports this option for backwards
              compatibility reasons only.

       -y     For  some filesystem-specific checkers, the -y option will cause
              the fs-specific fsck to  always  attempt  to  fix  any  detected
              filesystem corruption automatically.  Sometimes an expert may be
              able to do better driving the fsck manually.  Note that not  all
              filesystem-specific   checkers   implement   this   option.   In
              particular fsck.minix(8) and fsck.cramfs(8) does not support the
              -y option as of this writing.

AUTHOR

       Theodore Ts'o (tytso@mit.edu)

AVAILABILITY

       The  fsck  command  is  part of the util-linux package and is available
       from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.

FILES

       /etc/fstab.

ENVIRONMENT VARIABLES

       The fsck program's behavior is affected by  the  following  environment
       variables:

       FSCK_FORCE_ALL_PARALLEL
              If  this  environment  variable is set, fsck will attempt to run
              all of the specified  filesystems  in  parallel,  regardless  of
              whether  the filesystems appear to be on the same device.  (This
              is useful for RAID systems or high-end storage systems  such  as
              those  sold  by  companies  such  as  IBM or EMC.) Note that the
              fs_passno value is still used.

       FSCK_MAX_INST
              This environment variable will limit the maximum number of  file
              system  checkers  that  can be running at one time.  This allows
              configurations which have a large number of disks to avoid  fsck
              starting  too  many  file  system  checkers at once, which might
              overload CPU and memory resources available on the  system.   If
              this value is zero, then an unlimited number of processes can be
              spawned.  This is currently the default, but future versions  of
              fsck may attempt to automatically determine how many file system
              checks can be run based on gathering accounting  data  from  the
              operating system.

       PATH   The  PATH  environment  variable  is  used  to  find file system
              checkers.  A set  of  system  directories  are  searched  first:
              /sbin, /sbin/fs.d, /sbin/fs, /etc/fs, and /etc.  Then the set of
              directories found in the PATH environment are searched.

       FSTAB_FILE
              This environment variable allows  the  system  administrator  to
              override  the  standard  location of the /etc/fstab file.  It is
              also useful for developers who are testing fsck.

SEE ALSO

       fstab(5),  mkfs(8),  fsck.ext2(8)   or   fsck.ext3(8)   or   e2fsck(8),
       cramfsck(8),  fsck.minix(8),  fsck.msdos(8),  fsck.jfs(8), fsck.nfs(8),
       fsck.vfat(8), fsck.xfs(8), fsck.xiafs(8), reiserfsck(8).