What is “vnstat” Package?

Console-based network traffic monitor
For more details: http://humdi.net/vnstat/

Installation

• Open Terminal by pressing command+space then type terminal and hit Enter key.
• Install homebrew first.

  ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)" < /dev/null 2> /dev/null

• Install vnstat.

  brew install vnstat

Now, use vnstat!