Linux basics part-2

Creating Users in Linux

Let’s create a user, open your terminal in linux

$ sudo adduser <username>

Example:-

Now login created user

$ sudo su – <username>

Example:-

$ sudo su – pramod

$ whoami

What is Group in Linux?

Group is a generally a collection of users. In Linux, we can create the user accounts for users and add them in a different groups according to their role and set a privileges on them.

Instead of setting the privileges on users, create a group and set a privileges on that group and add users in that group. So, its save your time.

In Linux, there are two types of Groups

1. Primary – primary group is create when we create user and remember primary group’s username and group name is same.
2. Secondary – Secondary group is like existing group. for example, we have System Admin group, if we add a new user then the System Admin groups privileges automatically applied on new user.

Creating Groups in Linux

Let’s create Groups in Linux

$ sudo groupadd <group-name>

In below example, i have created one group named redient-security

Here,

Adding Users in group

$ sudo usermod -a -G <groupname> <username>

Here -a is append means adding and G is for Secondary group

For example

Adding Users in Multiple groups

In Linux, we can add one user in multiple groups.

$ sudo usermod -a -G <group-name>,<group-name> <username>

For example:-

$ sudo usermod -a -G redient-security,sredient pramod

Adding Multiple users in a group

$ sudo usermod -a -G <groupname> <username>

In below example, i have added redient and pramod users in redient-security group

Removing User from group

gpasswd is used to remove user from a group with -d option.

$ sudo gpasswd -d <username> <groupname>

For example:-

$ sudo gpasswd -d pramod sredient

Create New User and add in Existing group in one commands

$ sudo useradd -g users -G redient-security,sredient kovid

here, -g is primary group, users is primary group name, -G option is for secondary group, redient-security and sredient is secondary group name and kovid is new user name