Team not found while trying to run lessons in schools

I'm not sure if this is purposeful, but at startup ...

npm install learnyounode -g

.. the command in the terminal, the module is created in my home directory. When I try to run the "learnyounode" command from the directory in which I run the npm installation, I get the message "command not found". I looked at the usr directory, but the learnyounode directory is missing there.

After all the requests, I get the following output

/Users/username/npm/bin/learnyounode -> /Users/username/npm/lib/node_modules/learnyounode/learnyounode.js
learnyounode@0.4.1 /Users/username/npm/lib/node_modules/learnyounode
├── duplexer@0.1.1
├── through@2.3.4
├── boganipsum@0.1.0
├── hyperquest@0.1.8 (through@2.2.7)
├── concat-stream@1.2.1 (bops@0.0.6)
├── bl@0.6.0 (readable-stream@1.0.26)
├── through2-map@1.2.1 (through2@0.2.3, terminus@1.0.9)
└── workshopper@0.7.2 (map-async@0.1.1, tuple-stream@0.0.2, split@0.2.10, mkdirp@0.3.5,     xtend@2.1.2, colors-tmpl@0.1.0, terminal-menu@0.2.0, optimist@0.6.1, msee@0.1.1)

ps. I have a new node installation in my usr folder. I am more concerned that this problem will happen when I want to install other packages through NPM in the future.