Ignore urls in robot.txt with specific parameters?

Question

I would like for google to ignore urls like this:

http://www.mydomain.com/new-printers?dir=asc&order=price&p=3

All urls that have the parameters dir,

Answer 1

Here's a solutions if you want to disallow query strings:

Disallow: /*?*

or if you want to be more precise on your query string:

Disallow: /*?dir=*&order=*&p=*

You can also add to the robots.txt which url to allow

Allow: /new-printer$

The $ will make sure only the /new-printer will be allowed.

More info:

http://code.google.com/web/controlcrawlindex/docs/robots_txt.html

http://sanzon.wordpress.com/2008/04/29/advanced-usage-of-robotstxt-w-querystrings/