FILE

        LAS\FILE Mode Name [SINGLE|MULTIPLE] [/CONVERT] [/OVERWRITE]

    Selects the input and output files.
    FILE IN name        open an existing file as input
    FILE OUT name       open an existing file as output
    FILE BOTH name      select the same file for input and output.
    FILE UPDATE name    open a file for Updates only.
    FILE OUT name Type  creates a new output file, of the specified type
                        Option /OVERWRITE will force overwriting an existing fil
    FILE OUT name Type /CONVERT   converts an existing output file to
                                  the specified type

    Files have two different Types: SINGLE or MULTIPLE.

    File  of  type MULTIPLE allows to have several version of the same spec-
    trum (same ObservationNumber). This type is  the  "historical"  one  for
    CLASS. It can be opened in all modes.
    For file of type SINGLE, the ObservationNumber is a unique identifier of
    the spectrum: only one version exists. As a consequence a file  of  this
    type  cannot  in  general  be  opened both IN and OUT. Such files can be
    opened in mode UPDATE, which allows spectra to  be  modified  in  place,
    typically  via  a TAG or UPDATE command after a MODIFY. Command WRITE is
    not allowed in this mode.

    This new type has been introduced to simplify and  speed  up  On-The-Fly
    processing.


    The default extension is .30m but can can be specified using command SET
    EXTENSION.