You can define a symbol to invoke RDBPRE. Once you are in the
    RDBPRE environment, you can specify the programming language and
    the input file specification. For example:

    $ RDBPRE :== $RDBPRE
    $ RDBPRE
    INPUT FILE> MYPROG.RFO/FORTRAN

    A more convenient method is to define a symbol that invokes a
    particular preprocessor. For example, if you frequently use
    the preprocessor with FORTRAN data manipulation language (DML)
    programs:

    $ RFOR :== $RDBPRE/FORTRAN
    $ RFOR MYPROGRAM.RFO