Uninstall Homebrew

mac:~ hooni$ /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall)"

Install Homebrew

mac:~ hooni$ /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
mac:~ hooni$ brew update
mac:~ hooni$ brew doctor

Install gpg

mac:~ hooni$ brew install gnupg gnupg2

Install rvm

mac:~ hooni$ gpg2 --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3 \
> curl -sSL https://get.rvm.io | bash -s stable

Run rvm

mac:~ hooni$ source /Users/rhan/.rvm/scripts/rvm

Install ruby(Search what version is the latest)

mac:~ hooni$ rvm install 2.4.1

Install CocoaPods

mac:~ hooni$ gem install cocoapods

Install npm

mac:~ hooni$ brew install node