So I supposed you already ran curl -L get.yeoman.io | bash and went down the whole list to install all the tools. You also ran sudo npm install -g yeoman and it installed fine. But you are still getting that Yeoman [not installed] error, right?
Well, try issuing yeoman in your command line. If you get the standard “command not found” error, then it’s simply that yeoman is not in your $PATH.
To fix that, simply add the following line in your ~/.bash_profile file.
Then either you open a new terminal, or issue source ~/.bash_profile to refresh your $PATH.
Then now, run curl -L get.yeoman.io | bash and it should be happy. 😉
oh, I am using osx, if you are on other systems please adjust accordingly, thx!