In this chapter, we will explore the management of local user accounts and groups. You will gain an understanding of how to create, delete, and modify user accounts, ensuring proper access control on your system. We will also cover the essential security practices of changing passwords and adjusting password aging policies. Furthermore, you'll learn to effectively create, delete, and modify local groups and manage user memberships. Finally, we'll explore methods for configuring superuser access, empowering you to perform administrative tasks safely and effectively while adhering to best security practices. Please note that we will only cover local users. We do not cover NIS, LDAP, or any other systems.