One command to rule them all.

gn.sh

# Source this from your .bashrc/.zshrc

GIT_CORE="$(git --exec-path)"

gn() {
  command=$1
  shift
  if [ -f "${GIT_CORE}/git-${command}" ]; then
    git "$command" "$@"
  else
    if hash "git-${command}" 2>/dev/null; then
      git "$command" "$@"
    else
      npm "$command" "$@"
    fi
  fi
}