www and non-www crawl by bots

I want bots to index mydomain.com
I dont want bots to index www.domain.com

what can I do in robots.txt to have bots perform that???

 

Don't know if it can be done via robots.txt but I know you can do it using .htaccess

 

I already tried but it doesnt work for some reason
you can see all my configs at this forum http://ubuntuforums.org/showthread.php?t=884559
please advise how to fix

 

Try...

DirectoryIndex index.php
<FilesMatch .\.php>
ForceType application/x-httpd-php
</FilesMatch>
Options -MultiViews -Indexes +FollowSymlinks
RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} !^www\.
RewriteRule (.*) http://%{HTTP_HOST}/$1 [R=301,L] 
RewriteRule ^adser|ref|product\.php - [L]
RewriteCond $1 !(\.css)|(\.js)|(\.ico)|(\.swf)|(\.jpg)|(\.png)|(\.gif)|(^widgets.*)$ [NC]
RewriteRule ^(.*)$ index.php [QSA,NC,L]

Code (markup):

 

problem solved
it should look like this:

DirectoryIndex index.php
<FilesMatch .\.php>
ForceType application/x-httpd-php
</FilesMatch>
Options -MultiViews -Indexes +FollowSymlinks
RewriteEngine On
RewriteBase /
[COLOR="Red"]RewriteCond %{HTTP_HOST} ^www.example.com$ [NC]
RewriteRule ^(.*)$ http://example.com/$1 [R=301,L][/COLOR]
RewriteRule ^adser|ref|product\.php - [L]
RewriteCond $1 !(\.css)|(\.js)|(\.ico)|(\.swf)|(\.jpg)|(\.png)|(\.gif)|(^widgets.*)$ [NC]
RewriteRule ^(.*)$ index.php [QSA,NC,L]

Code (markup):

and it WORKS!

thanks for helping me out - I would never guess!

 

you can set in google webmaster tools. Gollow the folling steps:

1. logine google webmaster tools
2. Go to tools
3. that click on "Set preferred domain"

Here you can set.