oc -- Option Case

               default range             syntax
                   1,$                     oc

        The "c" (case) option toggles the same case mapping flag  that
        is  toggled  by the CTRL-Z control character, but also changes
        the marginal line letters to lower case (or back to upper), so
        that typing a shifted letter will still refer to a  line,  and
        typing an unshifted letter will do for a command letter.  This
        is  useful for handling large amounts of upper case text, such
        as Fortran programs.

        For general information about the option command, type "ho".
        See also "hoa".
        Fortraners see also "hof".