If you are on Linux or macOS, chances are you already know your shell. This is even more so if you have made any customizations to your command-line experience.

However, how would you check?

You echo the $SHELL variable.

echo $SHELL

On macOS, it returns thus:

macOSShell

On Linux, it returns thus:

linuxShell

Of course you could have changed your shell to something else, in which case whatever you changed to will be returned.

Happy hacking!