You could use the “su” command.
$ whoami user1 $ su - user2 Password: $ whoami user2 $ exit logout
If you want to log in as root, there’s no need to specify username:
$ whoami user1 $ su - Password: $ whoami root $ exit logout
Generally, you can use
sudo to launch a new shell as the user you want; the
-u flag lets you specify the username you want:
$ whoami user1 $ sudo -u user2 zsh $ whoami user2