wget tool to clone whole site with source code

wget --mirror --convert-links --adjust-extension --page-requisites --no-parent [URL]

Where:

--mirror tells wget to download the entire website recursively.
--convert-links converts links so that they work locally.
--adjust-extension adds suitable extensions to filenames.
--page-requisites downloads all the necessary files for a complete webpage.
--no-parent tells wget not to ascend to the parent directory when downloading recursively.

Replace [URL] with the URL of the website you want to download.