dosfsck.8 5.3 KB

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  1. .TH DOSFSCK 8 "December 31 1997" "Linux" "MAINTENANCE COMMANDS"
  2. .SH NAME
  3. dosfsck \- check and repair MS-DOS file systems
  4. .SH SYNOPSIS
  5. .ad l
  6. .B dosfsck|fsck.msdos|fsck.vfat
  7. .RB [ \-aAflnrtvVwy ]
  8. .RB [ \-d\ \fIpath\fB\ \-d\ \fI...\fB ]
  9. .RB [ \-u\ \fIpath\fB\ \-u\ \fI...\fB ]
  10. .I device
  11. .ad b
  12. .SH DESCRIPTION
  13. .B dosfsck
  14. verifies the consistency of MS-DOS file systems and optionally tries to
  15. repair them. The following file system problems can be corrected (in this
  16. order):
  17. .IP \-
  18. FAT contains invalid cluster numbers. Cluster is changed to EOF.
  19. .PD 0
  20. .IP \-
  21. File's cluster chain contains a loop. The loop is broken.
  22. .IP \-
  23. Bad clusters (read errors). The clusters are marked bad and they are
  24. removed from files owning them. This check is optional.
  25. .IP \-
  26. Directories with a large number of bad entries (probably corrupt). The
  27. directory can be deleted.
  28. .IP \-
  29. Files . and .. are non-directories. They can be deleted or renamed.
  30. .IP \-
  31. Directories . and .. in root directory. They are deleted.
  32. .IP \-
  33. Bad file names. They can be renamed.
  34. .IP \-
  35. Duplicate directory entries. They can be deleted or renamed.
  36. .IP \-
  37. Directories with non-zero size field. Size is set to zero.
  38. .IP \-
  39. Directory . does not point to parent directory. The start pointer is
  40. adjusted.
  41. .IP \-
  42. Directory .. does not point to parent of parent directory. The start pointer
  43. is adjusted.
  44. .IP \-
  45. Start cluster number of a file is invalid. The file is truncated.
  46. .IP \-
  47. File contains bad or free clusters. The file is truncated.
  48. .IP \-
  49. File's cluster chain is longer than indicated by the size fields. The file
  50. is truncated.
  51. .IP \-
  52. Two or more files share the same cluster(s). All but one of the files are
  53. truncated. If the file being truncated is a directory file that has already
  54. been read, the file system check is restarted after truncation.
  55. .IP \-
  56. File's cluster chain is shorter than indicated by the size fields. The file
  57. is truncated.
  58. .IP \-
  59. Clusters are marked as used but are not owned by a file. They are marked
  60. as free.
  61. .PD
  62. .LP
  63. Additionally, the following problems are detected, but not repaired:
  64. .IP \-
  65. Invalid parameters in boot sector.
  66. .PD 0
  67. .IP \-
  68. Absence of . and .. entries in non-root directories
  69. .PD
  70. .LP
  71. When \fBdosfsck\fP checks a file system, it accumulates all changes in memory
  72. and performs them only after all checks are complete. This can be disabled
  73. with the \fB\-w\fP option.
  74. .SH OPTIONS
  75. .IP \fB\-a\fP
  76. Automatically repair the file system. No user intervention is necessary.
  77. Whenever there is more than one method to solve a problem, the least
  78. destructive approach is used.
  79. .IP \fB\-A\fP
  80. Use Atari variation of the MS-DOS filesystem. This is default if
  81. \fBdosfsck\fP is run on an Atari, then this option turns off Atari
  82. format. There are some minor differences in Atari format: Some boot
  83. sector fields are interpreted slightly different, and the special FAT
  84. entries for end-of-file and bad cluster can be different. Under
  85. MS-DOS 0xfff8 is used for EOF and Atari employs 0xffff by default, but
  86. both systems recognize all values from 0xfff8...0xffff as end-of-file.
  87. MS-DOS uses only 0xfff7 for bad clusters, where on Atari values
  88. 0xfff0...0xfff7 are for this purpose (but the standard value is still
  89. 0xfff7).
  90. .IP \fB\-d\fP
  91. Delete the specified file. If more that one file with that name exists, the
  92. first one is deleted.
  93. .IP \fB\-f\fP
  94. Salvage unused cluster chains to files. By default, unused clusters are
  95. added to the free disk space except in auto mode (\fB-a\fP).
  96. .IP \fB\-l\fP
  97. List path names of files being processed.
  98. .IP \fB\-n\fP
  99. No-operation mode: non-interactively check for errors, but don't write
  100. anything to the filesystem.
  101. .IP \fB\-r\fP
  102. Interactively repair the file system. The user is asked for advice whenever
  103. there is more than one approach to fix an inconsistency.
  104. .IP \fB\-t\fP
  105. Mark unreadable clusters as bad.
  106. .IP \fB-u\fP
  107. Try to undelete the specified file. \fBdosfsck\fP tries to allocate a chain
  108. of contiguous unallocated clusters beginning with the start cluster of the
  109. undeleted file.
  110. .IP \fB\-v\fP
  111. Verbose mode. Generates slightly more output.
  112. .IP \fB\-V\fP
  113. Perform a verification pass. The file system check is repeated after the
  114. first run. The second pass should never report any fixable errors. It may
  115. take considerably longer than the first pass, because the first pass may
  116. have generated long list of modifications that have to be scanned for each
  117. disk read.
  118. .IP \fB\-w\fP
  119. Write changes to disk immediately.
  120. .IP \fB\-y\fP
  121. Same as \fB\-a\fP (automatically repair filesystem) for compatibility
  122. with other fsck tools.
  123. .LP
  124. If \fB\-a\fP and \fB\-r\fP are absent, the file system is only checked,
  125. but not repaired.
  126. .SH "EXIT STATUS"
  127. .IP 0
  128. No recoverable errors have been detected.
  129. .IP 1
  130. Recoverable errors have been detected or \fBdosfsck\fP has discovered an
  131. internal inconsistency.
  132. .IP 2
  133. Usage error. \fBdosfsck\fP did not access the file system.
  134. .SH FILES
  135. .IP "fsck0000.rec, fsck0001.rec, ..."
  136. When recovering from a corrupted file system, dosfsck dumps recovered data
  137. into files named 'fsckNNNN.rec' in the top level directory of the file system.
  138. .SH BUGS
  139. Does not create . and .. files where necessary. Does not remove entirely
  140. empty directories. Should give more diagnostic messages. Undeleting files
  141. should use a more sophisticated algorithm.
  142. .\".SH "SEE ALSO"
  143. .\"fs(5)
  144. .SH AUTHORS
  145. Werner Almesberger <werner.almesberger@lrc.di.epfl.ch>
  146. Extensions (FAT32, VFAT) by and current maintainer:
  147. Roman Hodek <roman@hodek.net>