According to MacHG documentation:
You can use the Mercurial command line version (via terminal) interchangeably with MacHg. You can freely download and install whatever version of Mercurial you want on your machine, and it will not conflict with MacHg, since the independent copy of Mercurial is bundled with the MacHg application. (In fact, MacHg does this to ensure that there are no conflicts or other problems with users of the Mercury configuration.)
hg serve
machg . , .