When you run git config --global core.editor emacs -nw, your shell splits the command line into words before invoking git. Git thus sees "emacs -nw" as two separate arguments. It only needs one to put into the config file, so the other is ignored. (Actually, that's a lie but you can check the man page for details.) You can put quotes around a series of words to tell your shell not to break them up: git config --global core.editor "emacs -nw" will give "emacs -nw" to git as a single argument which will do what you want.
The Git Protocol
Finally, we have the Git protocol. This is a special daemon that comes packaged with Git; it listens on a dedicated port (9418) that provides a service similar to the SSH protocol, but with absolutely no authentication. In order for a repository to be served over the Git protocol, you must create a git-daemon-export-ok file — the daemon won’t serve a repository without that file in it — but, other than that, there is no security. Either the Git repository is available for everyone to clone, or it isn’t. This means that there is generally no pushing over this protocol. You can enable push access but, given the lack of authentication, anyone on the internet who finds your project’s URL could push to that project. Suffice it to say that this is rare.
The Pros
The Git protocol is often the fastest network transfer protocol available. If you’re serving a lot of traffic for a public project or serving a very large project that doesn’t require user authentication for read access, it’s likely that you’ll want to set up a Git daemon to serve your project. It uses the same data-transfer mechanism as the SSH protocol but without the encryption and authentication overhead.
