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fsck



SYNOPSIS

       fsck [ -sACVRTNP ] [ -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 run filesystems on
       different physical disk drives in parallel to reduce total
       amount time 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 serial.  This is equiv­
       alent 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 direc­
       tories  listed  in  the PATH environment variable.  Please
       see the file system-specific checker manual pages for fur­
       ther details.


OPTIONS

       -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
              opts=fs-option.   If  an  options specifier is pre­
              sent, 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 search­
              ing 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 typi­
              cally used from the  /etc/rc  system  initalization
              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 multi­
              ple filesystem checks on the same physical disk.

              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 filesystems  to
              have  a fs_passno value of 2.  This will allow fsck
              to automatically run filesystem checkers in  paral­

       -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 solu­
              tion).

       -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  argu­
              ments  must  not take arguments, as there is no way
              for fsck to be able to properly guess  which  argu­
              ments 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 arbi­
              trarily 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 compli­
              cated 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.

       Currently,  standardized  file system-specific options are
       somewhat in flux.  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 compati­
              bility only.  This option is mapped to e2fsck's  -p
              option  which  is safe to use, unlike the -a option
              that most file system checkers support.

       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.)

       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  cur­
              rently 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  admin­
              istrator  to  override the standard location of the
              /etc/fstab file.  It is also use for developers who
              are testing fsck.


SEE ALSO

       fstab(5),    mkfs(8),   fsck.minix(8),   fsck.ext2(8)   or
       e2fsck(8), fsck.xiafs(8).

E2fsprogs version 1.34      July 2003                     FSCK(8)
  
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