FILE OUT

        LAS\FILE OUT Name
        LAS\FILE OUT Name SINGLE|MULTIPLE [/OVERWRITE]

    Open a Class file for writing.

    The  first  form  opens an old, already existing file, for appending new
    observations into it.

    The second form creates a new (empty) file. If a file with the same name
    already  exists,  it is overwritten if the option /OVERWRITE is present.
    An error is raised otherwise.
    A new ouput file can be of 2 different kinds:
      - the 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.
      - with the type SINGLE, the ObservationNumber is a  unique  identifier
        of  the spectrum: only one version exists. This type has been intro-
        duced to simplify and speed up On-The-Fly processing, in  particular
        at the telescope. It can not be opened in BOTH mode.