I generally have an emacs instance running someplace on my desktop, however I interact with git via the terminal. It gets to be quite annoying when git pulls up an editor and it isn’t emacs, the commands are different or not present.
To fix this I change my git editor to emacsclient:
git config --global core.editor 'emacsclient -nw'
The -nw tells it to open in the current terminal instead of opening the file in an existing emacs window/frame. Now I can edit away with all the power of emacs and hit C-x # when I’m done and it goes away.