fsck(1M)                      UNIX System V(UFS)                       fsck(1M)


NAME
      fsck (ufs) - file system consistency check and interactive repair

SYNOPSIS
      fsck [ -F ufs ] [generic_options] [special ...]
      fsck [ -F ufs ] [generic_options] [(-y|-Y)|(-n|-N)] [ -o p,b=#,w ] [
      special  ....  ]

DESCRIPTION
      generic_options are options supported by the generic fsck command.
      current_options are options supported by the s5-specific module of the
      fsck command.

      fsck audits and interactively repairs inconsistent conditions on file
      systems.  In this case, it asks for confirmation before attempting any
      corrections.  Inconsistencies other than those mentioned above can often
      result in some loss of data.  The amount and severity of data lost can be
      determined from the diagnostic output.

      fsck corrects innocuous inconsistencies such as: unreferenced inodes,
      too-large link counts in inodes, missing blocks in the free list, blocks
      appearing in the free list and also in files, or incorrect counts in the
      super block, automatically. It displays a message for each inconsistency
      corrected that identifies the nature of, and file system on which, the
      correction is to take place.  After successfully correcting a file
      system, fsck prints the number of files on that file system, the number
      of used and free blocks, and the percentage of fragmentation.

      The default action for each correction is to wait for the operator to
      respond either yes or no.  If the operator does not have write permission
      on the file system, fsck will default to a -n (no corrections) action.

      Inconsistencies checked are as follows:

            ⊕     Blocks claimed by more than one inode or the free list.
            ⊕     Blocks claimed by an inode or the free list outside the range
                  of the file system.
            ⊕     Incorrect link counts.
            ⊕     Incorrect directory sizes.
            ⊕     Bad inode format.
            ⊕     Blocks not accounted for anywhere.
            ⊕     Directory checks, file pointing to unallocated inode, inode
                  number out of range, absence of `.'  and `..'  as the first
                  two entries in each directory.
            ⊕     Super Block checks:  more blocks for inodes than there are in
                  the file system.
            ⊕     Bad free block list format.
            ⊕     Total free block and/or free inode count incorrect.

      Orphaned files and directories (allocated but unreferenced) are, with the
      operator's concurrence, reconnected by placing them in the lost+found
      directory.  The name assigned is the inode number.  If the lost+found


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fsck(1M)                      UNIX System V(UFS)                       fsck(1M)


      directory does not exist, it is created.  If there is insufficient space
      its size is increased.

      A file system may be specified by giving the name of the block or
      character special device on which it resides, or by giving the name of
      its mount point.

      The options are:

      -F ufs
            Specifies the ufs-FSType.

      -y | -Y
            Assume a yes response to all questions asked by fsck.

      -n | -N
            Assume a no response to all questions asked by fsck; do not open
            the file system for writing.

      -o    Specify ufs file system specific suboptions.  These suboptions can
            be any combination of the following:

            p     Check the filesystem non-interactively.  Exit if there is a
                  problem requiring intervention.

            b=#   Use the block specified as the super block for the file
                  system.  Block 32 is always an alternate super block.

NOTES
      Checking the character special device is almost always faster.

SEE ALSO
      checkfsys(1M), crash(1M), generic fsck(1M), mkfs(1M), ufs(4).





















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