This Tidy utility is intended to be used as a quick shell filter for display a bad formatted HTML like:
cat index.html | tidy
Tidy does some corrections to the original HTML, as it uses the parser guidelines of the W3C, but its intention is just to indent the code so you can easily spot the structure. Provably I will add some syntax highlighting of some sort.
It does not try to replace the much more advanced and better utility HTML Tidy.