FIND UPDATE

        LAS\FIND UPDATE [/OPT1 ...]

    The  input  index  will  first be appended with the new observations (if
    any) present in the input file. This saves time because a (much) smaller
    part of the input file is actually read. The current index is then reset
    and recomputed from the input index (i.e.  with  old  and  new  observa-
    tions), as usual.

    FIND  UPDATE  does  not  wait  for new data, but you can use the command
    NEW_DATA to do so.

    This keyword can be omitted if the SET FIND mode is UPDATE.