which_shell_am_i_using []

Q. Which shell am I using?

A. There are two ways

% echo $0
/usr/bin/zsh

% ps -p $$
  PID TTY          TIME CMD
29189 pts/1    00:00:00 zsh

If necessary, the last command can be parsed as follows.

% ps -hp $$|awk '{print $5}'
/usr/bin/zsh