    NAMEs are marked for automatic export to the environment of
    subsequently executed commands.  If the -f option is given,
    the NAMEs refer to functions.  If no NAMEs are given, or if `-p'
    is given, a list of all names that are exported in this shell is
    printed.  An argument of `-n' says to remove the export property
    from subsequent NAMEs.  An argument of `--' disables further option
    processing.
