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.