What option is used with the useradd command to specify the users login shell?

-s

When we create the user it assign the bash shell to user, to assign the different shell use the -s option. Example: useradd -s /bin/sh user1 : which creates the user user1 by assigning the /bin/sh shell. You can check the /etc/passwd file to check the user id, users private group id, home directory and login shell.