/FORMAT=type

    This positional qualifier must be given for both the input and
    output file specifications. The allowable types are ASCII, DX,
    and WPSFILE. The file extension of the input and output file
    must be given and they must agree with the selected format: for
    ASCII files the file extension must be .TXT, for DX files the
    file extension must be .DX, and for WPSFILE files the extension
    must be .WPL. Failure to use the proper extension will result in
    unpredictable results.