Package managers make it so much easier to install and update applications (for Operating Systems) or libraries (for programming languages). The most popular one for OS X is Homebrew.
An important dependency before Homebrew can work is the Command Line Tools for Xcode. These include compilers that will allow you to build things from source.
We can install Hombrew! In the terminal paste the following line (without the $), hit Enter, and follow the steps on the screen:
$ ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
One thing we need to do is tell the system to use programs installed by Hombrew (in /usr/local/bin) rather than the OS default if it exists. We do this by adding /usr/local/bin to your $PATH environment variable:
$ echo 'export PATH="/usr/local/bin:$PATH"' >> ~/.bash_profile
Alternatively, we can also insert /usr/local/bin to the first line of /private/etc/paths and reboot the Mac to change global paths loading order. Admin password may be required if you modify the file.
Open an new terminal tab with Cmd+T (you should also close the old one), then run the following command to make sure everything works:
$ brew doctor