1.) Install node.js from http://nodejs.org/download/ [Version 0.10.x would be good]
2.) Once that is completed, launch your "terminal"
run the command
sudo npm install -g particle-cli
3.) Once the installation is completed, you test that everything works by typing:
This is optional and added here in case you could not follow the github steps (https://github.com/spark/core-firmware#3-device-firmware-upgrade-utilities).
1.) Launch a Terminal and run this code:
ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
homebrew is installed, we will install DFU-util
brew install dfu-util
Sorry for the weird screenshot since i have it installed already. But you should probably get the idea