If you want to prevent Git from committing after editing the commit message, do:
This will make Vim to quit with an error code, preventing the commit operation from proceed.
Nice. Suggested mnemonic, "cancel-y quit"... "commit quitter"...
I've just had been leaving an empty commit message; git then cancels the commit.
Brevity is the soul of vim. :-) Great tip.
@alxndr: "Call-it quits", maybe?
You can also quit without writing to avoid a commit. This command is nice because it's useful in lots of situations.
Caution: your changes won't be saved by :cq
Watch out! If you're doing a git commit --amend, then you need :cq, otherwise you'll regenerate the commit with the same message (if you already pushed... d'oh).
git commit --amend