http://getbootstrap.com/getting-started/#download --> leads to - http://getbootstrap.com/getting-started/#grunt
--> leads to - https://github.com/joyent/node/wiki/Installing-Node.js-via-package-manager#debian-and-ubuntu-based-linux-distributions OR sudo spt-get install nodejs-legacy (not nodejs !!)
sudo apt-get install npm
AND Now "traverse back" the above tree
http://stackoverflow.com/questions/23285056/basic-installation-issue-for-gruntjs-for-use-with-bootstrap (Use 'whereis node_modules' to find its location)
http://www.andonescu.ro/2014/06/20/how-to-fix-grunt-error-cannot-find-module-lru-cache/