DCHECK(1M)                                             DCHECK(1M)

     NAME
          dcheck - file system directory consistency check

     SYNOPSIS
          dcheck [ -i numbers ] [ filesystem ]

     DESCRIPTION
          Dcheck reads the directories in a file system and compares
          the link-count in each i-node with the number of directory
          entries by which it is referenced.  If the file system is
          not specified, a set of default file systems is checked.

          The -i flag is followed by a list of i-numbers; when one of
          those i-numbers turns up in a directory, the number, the i-
          number of the directory, and the name of the entry are
          reported.

          The program is fastest if the raw version of the special
          file is used, since the i-list is read in large chunks.

     FILES
          Default file systems vary with installation.

     SEE ALSO
          icheck(1), filsys(5), clri(1), ncheck(1)

     DIAGNOSTICS
          When a file turns up for which the link-count and the number
          of directory entries disagree, the relevant facts are
          reported.  Allocated files which have 0 link-count and no
          entries are also listed.  The only dangerous situation
          occurs when there are more entries than links; if entries
          are removed, so the link-count drops to 0, the remaining
          entries point to thin air.  They should be removed.  When
          there are more links than entries, or there is an allocated
          file with neither links nor entries, some disk space may be
          lost but the situation will not degenerate.

     BUGS
          Since dcheck is inherently two-pass in nature, extraneous
          diagnostics may be produced if applied to active file sys-
          tems.