Please include this information:
$ grafana-server -v
Version 4.0.1 (commit: unknown-dev)
brew install grafana
Maybe is a configuration issue but grafana-server installed clean in a mac OS X will just finish.
It will be good if the default configuration file would make the grafana-server not finish and do something instead or would at least print out the problem.
As it is now as a new user, I have no idea of what's the issue