htmltree generates an HTML file, written onto the standard output, that contains a "map" of a directory. The format of this map can be varied to a large extent by means of the htmltree command line options explained in this How to use htmltree page. This page also can be generated by htmltree itself, by running htmltree -h. One can also use the pod2man and/or pod2html commands supplied with Perl to generate man page from the htmltree code downloaded above.