CLRI(VIII)                  10/31/73                   CLRI(VIII)


     clri - clear i-node


     clri i-number [ filesystem ]


     Clri writes zeros on the 32 bytes  occupied  by  the  i-node

     numbered  i-number.   If  the file system argument is given,

     the i-node resides on  the  given  device,  otherwise  on  a

     default  file  system.   The  file system argument must be a

     special file name referring to a device  containing  a  file

     system.   After  clri,  any blocks in the affected file will

     show up as ``missing'' in an icheck of of the file system.

     Read and write permission is required on the specified  file

     system device.  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 entry 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.


     Whatever the default file system is,  it  is  likely  to  be

     wrong.  Specify the file system explicitly.

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