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

Register your website with Google WebMaster Tools. There you can tell Google how to deal with your parameters.

Site Configuration -> URL Parameters

You should have the pages that contain those parameters indicate that they should be excluded from indexing via the robots meta tag. e.g.