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

       clri - clear i-node

       clri filesystem i-number ...

       Clri  writes  zeros  on  the  i-nodes with the decimal i-numbers on the
       filesystem.  After clri, any blocks in the affected file will  show  up
       as `missing' in an icheck(1) of the filesystem.

       Read  and write permission is required on the specified file system de‐
       vice.  The i-node becomes allocatable.

       The primary purpose of this routine is to remove a file which for  some
       reason  appears  in no directory.  If it is used to zap an i-node which
       does appear in a directory, care should be taken to track down the  en‐
       try  and  remove it.  Otherwise, when the i-node is reallocated to some
       new file, the old entry will still point to that file.  At  that  point
       removing  the  old entry will destroy the new file.  The new entry will
       again point to an unallocated i-node, so the whole cycle is  likely  to
       be repeated again and again.


       If the file is open, clri is likely to be ineffective.