Read URLs from file, in which case no URLs need to be on
the command line. If there are URLs both on the command line and
in an input file, those on the command lines will be the first ones to
be retrieved. The file need not be an HTML document (but no
harm if it is)---it is enough if the URLs are just listed
sequentially.
However, if you specify `--force-html', the document will be
regarded as `html'. In that case you may have problems with
relative links, which you can solve either by adding <base
href="url"> to the documents or by specifying
`--base=url' on the command line.