Now that your Terminal is setup, it's time to update Ubuntu's Advanced Packaging Tool or APT for short. If you've never heard of a package manager, think of it as an App Store of free command line programs.
To get started, run the following commands.
sudo apt-add-repository -y ppa:fish-shell/release-2
sudo apt-add-repository -y ppa:webupd8team/sublime-text-3
sudo add-apt-repository -y ppa:git-core/ppa
sudo apt-get update
TIP: This may require your account password which will not appear on the screen as you type.