OPEN

OPEN [EXCLUSIVE]

    { {INPUT } { file [WITH NO REWIND] } ... } ...
      {OUTPUT}        [lock-option   ]
      {I-O   }
      {EXTEND}

note: lock-option may be either of these formats:

 { ALLOWING {NO OTHERS} }
            {READERS  }
            {WRITERS  }
            {UPDATERS }
            {ALL      }

 { WITH {LOCK       }   }
        {MASS-UPDATE}