Linux User Administration Part 1

User Accounts
Because Linux is a multi-user system, the task of adding and
maintaining user accounts is common in Linux system
administration.
Upon a successful installation of a Linux distribution, two user
accounts are configured: the root user and a normal user.
These two user accounts represent the two basic types of users
that are configurable with Linux.

The first type, the root user,is unique for several reasons.
It is the only user account with system wide privileges.
Other accounts can be set up as an exact clone of the root
user account, but it is strongly discouraged.

Systems Accounts
In your Linux distribution, you will see a number of accounts set
up, like bin, daemon, adm, Ip, sync, shutdown, mail, operator,
and others.
They are called "system accounts" and are used for varying
purposes, some self-explanatory, some not.
These accounts do not have passwords because they are not
designed for login.
These special-purpose accounts are also called non-login
accounts. They need to be in your password file.

Privileges of root Account
System administration tasks are performed from the root or
superuser account.
The following list summarizes some of the duties and privileges of
a system administrator:
Has complete access to all files and directories regardless of
owner and permissions
Controls user account administration
Performs system maintenance
Halts the system when necessary
Sets up initial user passwords
Changes passwords when necessary.
Installs software on the system