Which shell I am using in mac
Assuming you're using the standard Terminal.app and you've verified that it is indeed configured to use your default login shell, as described in NobodyNada's helpful answer:
To see what shell is currently running (which may or may not be your default shell), use:
ps -o comm= $$To see what shell is your default shell, run:
echo $SHELL
macOS's Terminal allows you to specify the shell in its preferences. By default, it is set to use your login shell, but it looks like you've overridden it to use Bash.
In the General tab of Terminal's preferences, set it to "Default login shell," to prevent your login shell from being overridden:
Also, make sure the "Run command" checkbox is not checked in the Shell tab of your profiles' settings:
