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
EDITOR environment variables in your terminal resource file
export VISUAL=vim export EDITOR="$VISUAL"
If you wonder why both ‘VISUAL’ and ‘EDITOR’ set, please look at : VISUAL vs EDITOR