Hmmmm, you may have noticed that DigitalOcean provides one-step ghost blog setup -- you can directly choose Ghost 0.4.2 on Ubuntu 12.04. But, as you see, it's 12.04 which may does'nt meet our needs.
E.g. its vim version is 7.3, compiled in 2011.
So, you may think: I should customize all by myself, and certainly I can make it. Then, you would have installed everything needed. As you cd ghost && npm start, only to find :
/usr/bin/env: node: No such file or directory
npm WARN This failure might be due to the use of legacy binary "node"
npm WARN For further explanations, please read
/usr/share/doc/nodejs/README.Debian