dosfsck

       fsck.fat [OPTIONS] DEVICE

DESCRIPTION
       fsck.fat  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.

       *   Clusters are marked as used but are not owned by a file.  They  are
           marked as free.

       Additionally, the following problems are detected, but not repaired:
           the least destructive approach is used.

       -A  Use  Atari  variation of the MS-DOS filesystem.  This is default if
           fsck.fat 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).

       -b  Make read-only boot sector check.

       -d PATH
           Delete the specified file.  If more than one file  with  that  name
           exist,  the  first  one  is deleted.  This option can be given more
           than once.

       -f  Salvage unused cluster chains to files.  By default,  unused  clus-
           ters 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.

       -p  Same as -a, for compatibility with other *fsck.

       -r  Interactively repair the filesystem.  The user is asked for  advice
           whenever  there  is more than one approach to fix an inconsistency.
           This is the default mode and the option is only retained for  back-
           wards compatibility.

       -t  Mark unreadable clusters as bad.

       -u PATH
           Try  to  undelete the specified file.  fsck.fat tries to allocate a
           chain of contiguous unallocated clusters beginning with  the  start
           cluster  of the undeleted file.  This option can be given more than
           once.

       -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 fix-
           able 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
           When recovering from a corrupted filesystem, fsck.fat 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
       fatlabel(8)
       mkfs.fat(8)

HOMEPAGE
       The home  for  the  dosfstools  project  is  its  GitHub  project  page
       <https://github.com/dosfstools/dosfstools>.

AUTHORS
       dosfstools  were  written  by  Werner  Almesberger <werner.almesberger@
       lrc.di.epfl.ch>, Roman Hodek  <Roman.Hodek@informatik.uni-erlangen.de>,
       and others.  The current maintainer is Andreas Bombe <aeb@debian.org>.

3.0.28                            2015-05-16                       FSCK.FAT(8)
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