term% ls -F
term% cat index.txt
DCHECK(1M)                                                          DCHECK(1M)

       dcheck - file system directory consistency check

       dcheck [ -i numbers ] [ filesystem ]

       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 direc‐
       tory, 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.

       Default file systems vary with installation.

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

       When  a file turns up for which the link-count and the number of direc‐
       tory 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 en‐
       tries 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 de‐

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