npm

geckodriver

WebDriver proxy that enables remote control of Firefox browsers

brewmacoslinux
Try with needOr install directly
Source

About

WebDriver <-> Marionette proxy

Commands

geckodriver

Examples

Start geckodriver on default port 4444$ geckodriver
Start geckodriver on a specific port$ geckodriver --port 9876
Start geckodriver with verbose logging$ geckodriver --log trace