dosfsck



SYNOPSIS
       dosfsck|fsck.msdos|fsck.vfat  [-aAflnrtvVwy]  [-d PATH -d ...] [-u PATH
       -u ...] DEVICE


DESCRIPTION
       dosfsck verifies the consistency of MS-DOS filesystems  and  optionally
       tries to repair them.

       The following filesystem problems can be corrected (in this order):

       *   FAT contains invalid cluster numbers. Cluster is changed to EOF.

       *   File's cluster chain contains a loop. The loop is broken.

       *   Bad  clusters  (read  errors). The clusters are marked bad and they
           are removed from files owning them. This check is optional.

       *   Directories with a large number of bad entries (probably  corrupt).
           The directory can be deleted.

       *   Files . and .. are non-directories. They can be deleted or renamed.

       *   Directories . and .. in root directory. They are deleted.

       *   Bad filenames. They can be renamed.

       *   Duplicate directory entries. They can be deleted or renamed.

       *   Directories with non-zero size field. Size is set to zero.

       *   Directory  .  does not point to parent directory. The start pointer
           is adjusted.

       *   Directory .. does not point to  parent  of  parent  directory.  The
           start pointer is adjusted.

       *   Start cluster number of a file is invalid. The file is truncated.

       *   File contains bad or free clusters. The file is truncated.

       *   File's  cluster  chain is longer than indicated by the size fields.
           The file is truncated.

       *   Two or more files share the same cluster(s). All  but  one  of  the
           files  are  truncated.  If  the file being truncated is a directory
           file that has already been read, the filesystem check is  restarted
           after truncation.

       *   File's  cluster chain is shorter than indicated by the size fields.
           The file is truncated.



OPTIONS
       -a  Automatically repair the filesystem. No user intervention is neces-
           sary. Whenever there is more than one method to  solve  a  problem,
           the least destructive approach is used.

       -A  Use  Atari  variation  of the MS-DOS filesystem. This is default if
           dosfsck is run on an Atari, then this option turns off  Atari  for-
           mat.  There  are  some minor differences in Atari format: Some boot
           sector fields are interpreted slightly different, and  the  special
           FAT entries for end-of-file and bad cluster can be different. Under
           MS-DOS 0xfff8 is used for EOF and Atari employs 0xffff by  default,
           but  both  systems  recognize  all  values  from 0xfff8...0xffff as
           end-of-file. MS-DOS uses only 0xfff7 for  bad  clusters,  where  on
           Atari values 0xfff0...0xfff7 are for this purpose (but the standard
           value is still 0xfff7).

       -d  Delete the specified file. If more that one  file  with  that  name
           exists, the first one is deleted.

       -f  Salvage unused cluster chains to files. By default, unused clusters
           are added to the free disk space except in auto mode (-a).

       -l  List path names of files being processed.

       -n  No-operation mode: non-interactively check for  errors,  but  don't
           write anything to the filesystem.

       -r  Interactively  repair  the filesystem. The user is asked for advice
           whenever there is more than one approach to fix an inconsistency.

       -t  Mark unreadable clusters as bad.

       -u  Try to undelete the specified file. dosfsck  tries  to  allocate  a
           chain  of  contiguous unallocated clusters beginning with the start
           cluster of the undeleted file.

       -v  Verbose mode. Generates slightly more output.

       -V  Perform a verification pass. The filesystem check is repeated after
           the  first  run.  The  second  pass should never report any fixable
           errors. It may  take  considerably  longer  than  the  first  pass,
           because  the  first  pass may have generated long list of modifica-
           tions that have to be scanned for each disk read.

       -w  Write changes to disk immediately.

       -y  Same as -a (automatically repair filesystem) for compatibility with
           other fsck tools.

       Note:  If -a and -r are absent, the filesystem is only checked, but not
       repaired.

           When  recovering  from a corrupted filesystem, dosfsck dumps recov-
           ered data into files named 'fsckNNNN.rec' in the top  level  direc-
           tory of the filesystem.


BUGS
       Does  not  create  .  and  ..  files  where  necessary. Does not remove
       entirely empty  directories.  Should  give  more  diagnostic  messages.
       Undeleting files should use a more sophisticated algorithm.


SEE ALSO
       dosfslabel(8)
       mkdosfs(8)


HOMEPAGE
       More   information  about  dosfsck  and  dosfstools  can  be  found  at
       <http://www.daniel-baumann.ch/software/dosfstools/>.


AUTHORS
       dosfstools  were   written   by   Werner   Almesberger   <werner.almes-
       berger@lrc.di.epfl.ch>,  Roman Hodek <Roman.Hodek@informatik.uni-erlan-
       gen.de>,  and  others.  The  current  maintainer  is   Daniel   Baumann
       <daniel@debian.org>.



3.0.9                             2010-01-31                        DOSFSCK(8)
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