in reply to replacing close-single-quote with apostrophe

That's the utf8 encoding of the codepoint of Right Single Quotation Mark

You should better rely on proper encoding of your script and the input layer and just write s/`/'/g like choroba showed you in the second part.

Fiddling with bytes instead of characters isn't a clean approach.

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery