dosfsck; man page

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SYNOPSIS
       dosfsck [-aAflnrtvVwy] [-d path -d ...]  [-u path -u ...]  device

DESCRIPTION
       dosfsck  verifies the consistency of MS-DOS file systems and optionally
       tries to repair them. The following file system problems  can  be  cor‐
       rected (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 cor‐
              rupt). The directory can be dropped.
       -      Files . and .. are  non-directories.  They  can  be  dropped  or
              renamed.
       -      Directories . and .. in root directory. They are dropped.
       -      Bad file names. They can be renamed.
       -      Duplicate directory entries. They can be dropped 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 trun‐
              cated.
       -      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  file system 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:

       -      Invalid parameters in boot sector.
       -      Absence of . and .. entries in non-root directories

       When dosfsck checks a file system, it accumulates all changes in memory
       and  performs them only after all checks are complete. This can be dis‐
       abled with the -w option.

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

       -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.

       -r     Interactively  repair  the  file  system.  The user is asked for
              advice whenever there is more than one approach to fix an incon‐
              sistency.

       -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 file system 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
              modifications 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.

       If -a and -r are absent, the file  system  is  only  checked,  but  not
       repaired.

EXIT STATUS
       0      No recoverable errors have been detected.

       1      Recoverable  errors have been detected or dosfsck has discovered
              an internal inconsistency.

       2      Usage error. dosfsck did not access the file system.

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.

AUTHORS
       Werner   Almesberger   <werner.almesberger@lrc.di.epfl.ch>   Extensions
       (FAT32, VFAT) by and current maintainer: Roman Hodek <roman@hodek.net>
--TechZilla