Write a user login program that includes the following functions:

• Input the user ID and password. Use the getpass function to keep from echoing the password.
• Use either the exist /etc/passwd file or your own file to verify that the account exists.
• Use your own shadow file to contain the passwords which should be store in encrypted form. Use the crypt function for encrypting passwords.
• If the ID and password check out OK, set the user using the setuid function
• If the userid is not preceeded by an asterix, execute the normal login program.
• Replace /bin/login with your login program. Save /bin/login under the name /bin/OLDlogin