Page 209 - DCAP602_NETWORK_OPERATING_SYSTEMS_I

Unit 11: User Accounts

adding users notes

One of the most important activities in administering a Linux box is the addition of users. Here
you’ll find some simple examples to provide a foundation for future unit. It is not intended to be
comprehensive, but is a good memory refresher. You can use the command man useradd to get
the help pages on adding users with the useradd command or the man usermod to become more
familiar with modifying users with the usermod command.

Did u know? What are permissions to the root users?

11.1.1 who is the super user?

The super user with unrestricted access to all system resources and files in Linux is the user
named root. This user has a user ID, of 0 which is universally identified by Linux applications
as belonging to a user with supreme privileges. You will need to log in as user root to add new
users to your Linux server.

Note When installing Ubuntu Linux systems, you are prompted to create a primary
user that is not root. A root user is created but no password is set, so you initially cannot
log in as this user.

11.1.2 How to add users?

Adding users takes some planning; read through these steps below before starting:
1. Arrange your list of users into groups by function. In this example there are three groups
“parents”, “children” and “soho”.
Parents Children Soho
Paul Alice Accounts

Jane Derek Sales
2. Add the Linux groups to your server:

[root@bigboy tmp]# groupadd parents
[root@bigboy tmp]# groupadd children
[root@bigboy tmp]# groupadd soho
3. Add the Linux users and assign them to their respective groups
[root@bigboy tmp]# useradd -g parents paul
[root@bigboy tmp]# useradd -g parents jane
[root@bigboy tmp]# useradd -g children derek
[root@bigboy tmp]# useradd -g children alice

[root@bigboy tmp]# useradd -g soho accounts
[root@bigboy tmp]# useradd -g soho sales
If you don’t specify the group with the -g, RedHat/Fedora Linux creates a group with
the same name as the user you just created; this is also known as the User Private Group
Scheme. When each new user first logs in, they are prompted for their new permanent
password.

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