I prefer to write my git commit messages in Vim instead of nano or emacs or anything. To set this ‘globally’, change your Git‘s core.editor:

$ git config --global core.editor "vim"

If you also want to set Vim for other programs as well, set the standardized VISUAL and EDITOR environment variables in your terminal resource file (.zshrc, .bashrc, config.fish etc.)

export VISUAL=vim
export EDITOR="$VISUAL"

All done!

P.S:

Info

If you wonder why both ‘VISUAL’ and ‘EDITOR’ set, please look at : VISUAL vs EDITOR