In our quest for knowledge and learning new technologies, we do a lot of researching , reading and community activities . Sometimes we find many topic that we think worth sharing for the benefit of our clientsand other web professionals all over the world. Enjoy and participate by commenting and sharing.
change the content of the robots.txt in the root folder to
thats it , google will never look at your site untill you remove these lines. So dont forget to replace these codes with original Joomla robots.txt file contents later.
Further reading http://antezeta.com/news/avoid-search-engine-indexing
Then here is the way to add those files in to the joomla extension the proper way.
Joomla! CMS uses the templates/system/error.php file to handle several HTTP Status errors, including "403 Forbidden", "404 Not Found", and "500 Internal Server" Errors. You may style the error results by directly changing the templates/system/error.php.
But it is not advisable to hack core system files as those changes can be lost in an event of a Joomla update process!.
So best way is to use the template overriding and add a error.php file to your default template and customize it.