Notes to Debian users:

1.  `markdown2pdf` has been removed, since pandoc now includes `pdf`
    as a writer option.  You can replace

        markdown2pdf foo.txt

    with

        pandoc foo.txt -o foo.pdf

    Note that unlike `markdown2npdf`, `pandoc` requires that the output
    filename be specified explicitly.

2.  If you intend to use the html2markdown script, you should install
    tidy, plus either wget or w3m.