My site can be accessed by either http://example.com or http://beta.example.com. The sub domain beta is the same site but a different version and I want users to be able to use the beta but any links gained on the beta domain I want the link juice to pass to the main domain.  How can this be done?
Allow users to access my beta subdomain but pass link juice to the main site
seo;redirects;robots.txt;backlinks
Never treat Googlebot any different than actual site visitorsYou should never treat Google bot any different from actual users. Redirecting Googlebot using user agent or other similar tactics and not users will likely harm your site as its against Google's guideline rules.Cosmetic changes say hello to canonical linksIf the beta site has the same content but different cosmetic changes through CSS then you should use canonical links pointing to the master pages that way any links gained on beta will pass to the main domain.If the content is differentIf the content is actually different then you should not attempt to redirect Juice as this again will not go well with Google, if you want the juice to flow to the main site then you should run it on the main domain with a sub folder /beta/.