How to get shell to self-detect using zsh or bash

Question

I\'ve a question on how to tell which shell the user is using. Suppose a script that if the user is using zsh, then put PATH to his .zshrc and if using bash sho

Answer 1

the other answers fail with set -u

  if [ ! -z ${ZSH_VERSION+x} ]; then
    echo "this is zsh"
    echo ${(%):-%x}
  elif [ ! -z ${BASH_VERSION+x} ]; then
    echo "this is bash"
    echo $BASH_SOURCE
  else
    echo "not recognized"
  fi