Where can I find documentation on this? Just using ``mv prefix/lib, lib`` does not work, it gives the error:

    /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/fileutils.rb:506:in `rename'
    Errno::EINVAL: Invalid argument - /usr/local/Cellar/subversion/1.8.3/lib or /usr/local/Cellar/subversion/1.8.3/lib/lib