How can I configure git help to use Firefox?

I was using Git on a Windows box and the git bash always used the web version for help. I really liked this and I am trying to do the same on my mac. I ran: ``` $ git config --global help.format web $ git config --global web.browser firefox ``` and the output of a `help` command is: ``` $ The browser firefox is not available as 'firefox'. ``` I then set: ``` $ git config --global browser.firefox.path /Applications/Firefox.app/Contents/MacOS/firefox-bin ``` Since I usually have firefox open, it now cries: A copy of Firefox is already open. Only one copy of Firefox can be open at a time. The real command I would like git to use is `open -a Firefox.app somefile`. I tried setting `browser.firefox.cmd` with no avail. My question: how can I configure git to use the web version and call/use firefox in a way that won't cause issue if it's already open?