The format file determines the layout for the table of contents and the type of information it will contain. It consists of up to four statement types labeled a, tt, ord and sel respectively. If used, these statements must appear in this order. The format file may contain only one each of the a, ord and sel statements, and up to 32 tt statements. It may not contain any blank lines. If you want to use blank lines to improve readability, type a space or press TAB before pressing RETURN.