-f format Specifies the format of the input and output files which can have
o txt (default value) Input and output files are in
o html Input and output files are in "html" format. This
"html" is the one acceptd by the vast majority of web browsers.
o rtf Input and output files are in "rtf" format. The
accepted "rtf" is the one generated by Microsoft WordPad (C) and
Microsoft Office (C) up to and including Office-97.
infile Input file (stdin by default).
outfile Output file (stdout by default).