smart-quotes.awk can be used with awk to convert html file contents' quotes to smart quotes ("" -> “” and '' -> ‘’).
First run the script and create a new file with the output.
awk -f ~/Development/marxists.org/smart-quotes.awk input.htm > output.htm
Then run a difftool and check the output. I like to run colordiff
and pipe it to less
with a pattern for highlighting the characters we just attempted to edit.