NPM does not install anything : it hangs

Question

Whenever I want to install a module with NPM, it hangs at that stage:

npm install express
npm http GET https://registry.npmjs.org/express

And that's it. It has that behavior for anything I input instead of express. I installed nodejs and nvm that way (Ubuntu 13.10):

sudo apt-get install python-software-properties
sudo add-apt-repository ppa:chris-lea/node.js
sudo apt-get update
sudo apt-get install nodejs

I tried looking on the Internet and GitHub and I found a closed issue about npm hanging forever when trying to install a module.. but it was a really old issue. Before I ask the developers, am I missing something obvious ?

I tried compiling both nodejs and npm but the result was the same.

EDIT: npm install express -verbose -> http://pastebin.com/tGY3V6Ly Error:

npm info retry will retry, error on last attempt: Error: tunneling socket could not be established, cause=140072708810560:error:140770FC:SSL   routines:SSL23_GET_SERVER_HELLO:unknown protocol:../deps/openssl/openssl/ssl/s23_clnt.c:766:

Answer 1

Try without https:

npm config set registry http://registry.npmjs.org/

Answer 2

I had this problem inside a Windows git bash terminal - reinstalling the latest version of git bash fixed it

Answer 3

After an hour of struggling, I cleaned .npm and node_modesl/.staging directories, and problem just gone! (replace the paths with your own)

yes|rm /root/.npm/* -R
yes|rm /path/to/node_modules/.staging/* -R
npm install