Block Google and bots using htaccess and robots.txt

Robots.txt
User-agent: *
Disallow: /

.htaccess

RewriteEngine on
RewriteCond %{HTTP_USER_AGENT} AltaVista [OR]
RewriteCond %{HTTP_USER_AGENT} Googlebot [OR]
RewriteCond %{HTTP_USER_AGENT} msnbot [OR]
RewriteCond %{HTTP_USER_AGENT} Slurp
RewriteRule ^.*$ “http\:\/\/domainname\.com.au” [R=301,L]

Deactivate Magento store using .htaccess temporarily

Here is quick snippet of code that we use all the time when upgrading or moving a Magento store. This will stop people from creating accounts, placing orders, etc… while you are in the middle of heavy database work.
Add this to your .htaccess file in your root directory and only your IP address will be able to view your website. All other visitors will get redirected to an “updating” page.
Add this to your .htaccess file (directly after RewriteEngine On):

RewriteCond %{REMOTE_HOST} !^123.45.67.89
RewriteCond %{REQUEST_URI} !/updating.html$
RewriteRule .*$ /updating.html [R=302,L]

Do not forget to create a file called updating.html and put the message that you want visitors to see while your site is down.