Shell script [bash] to create a new user

Create a script to create new user accounts Write a shell script that creates a user in the following manner: a. Show a new user menu that asks for the following: i. a username (must be a valid user name, lowercase, six characters or more, unique meaning the user name does not exist already). If not a valid username, then show an error. ii. generate a password for the user which must be changed the first time the user logs in iii. a group (ask the user what group to add the new user to. Give an error if the group does not exist) iv. a home directory that the user prefers. i.e /home/education/username b. create preset disk quota for their home directory (for instance 250 MB), i. make the script send an "over quota" warning e-mail (even though there's nothing in the user home directory at this point)