Install Bash-it:
https://github.com/Bash-it/bash-it
Choose powerline theme:
https://github.com/Bash-it/bash-it/wiki/Themes#powerline
Install powerline fonts (I use Source Code Pro):
https://github.com/powerline/fonts/tree/master/SourceCodePro
Install terminal theme:
Set Source Code Pro as font for powerline theme in Terminal preferences.