Google is unfriendly to searching for verbatim strings with characters like $ and #. Is there a search engine that supports searching for verbatim strings?
If you're actually looking for code examples, I like using Krugle. It has a fairly comprehensive set of open source code.
If you're searching for error messages and the like, I still haven't found anything...
Try http://www.google.com/codesearch
Just remember that it's a REGEXP language, so to search for $value, use \$value.
For example:
http://www.google.com/codesearch?hl=en&lr=&q=\%24value&sbtn=Search
this one would be cool if more was covered....
or
http://www.gotapi.com/html for the html version
you can also go here and check out more, obviously
I don't think there is an easy way around something like this. When I work with Tcl I search at ActiveState's website, when I do C# I go to MSDN, Python, I go to python.org. Is there a specific reason you need a central location rather than going to the handful of main programming sites for each language/environment ( besides being lazy =D )? Maybe a better question would be "What sites are the best to search for [insert favorite programming language]?" because I think you'll find that most search engines have to make exclusions for performance since so many people use them for different reasons. Better to just find a site that focuses on your subject matter and then search.