I was thinking it would be a good idea to have an "official" yaml command line tool. The tool would make it possible for shell scripts to work with yaml documents. It should be able to do things like read a value give a "ypath" (whatever that is exactly), set a value, handle possible conversions (e.g. json<->yaml), etc.
I have a ruby script that I created that is basically like this called `yc` (https://github.com/rubyworks/yc