Unix system security is based on controlling access to files (programs and data). You control access by defining user and group accounts and granting these accounts different levels of file access. The user accounts are protected by passwords.
Administrative accounts are given access to system data and tools that allow them to perform system maintenance. These accounts include root, sys, bin, and adm.
Several account administration files are used to store information associated with user and group accounts, such as account names and passwords.
The root, or superuser, account is a special administrative account that provides the ultimate in access to data and services because it can override any file ...