Linux Add User

Introduction to Linux Add User

In the Linux operating system, the adduser command is used to create or add the user to the Linux server. There are different ways to add users to the Linux environment like useradd, adduser. The Linux ecosystem is supporting the multi-user. Hence it is more important to keep proper track and control on user and group levels. As per the requirement, we can configure or limit the access for the new user.

Note: The adduser command is similar to the useradd command only. Because it is a symbolic link in between it, hence both the command having similar behavior.

Syntax of Adduser command

useradd [options ] LOGIN
useradd -D
useradd -D [options]

1. useradd: We can use the “useradd” keyword in the syntax or command. It will take different arguments likeOPTION, LOGIN type, user name, etc. As per the provided arguments, it will create the new user with the required configuration.
2. OPTION: We can provide the different flags as options that are compatible with the “useradd” command.
3. LOGIN: We can provide the different LOGIN type to the “useradd” command. Accordingly, It will provide shell access.

Note: The useradd and adduser command is nothing but a similar command.

How does Linux Adduser Command work?

The Linux environment is supporting the multi-user session handler. Due to which the number of users can access the different data. Hence it is mandatory to keep the proper user in the necessary group with proper access and user-config.

When we are creating any new user on the Linux environment. The below process will happen every time.

1. The controller will edit the below files for the new user account.

• /etc/passwd
• /etc/shadow
• /etc/group
• /etc/gshadow

2. It will create the new home directory for the new user (default path is /home/$new_username)

3. It will automatically setup the necessary ownership and the permissions on the home directory.

In the “/etc/passwd” file, we will get all the detailed information of the entire user. As per the Linux system administrator, it is very important to understand the below points.

• Username: The user name is “test_user”. The same user name is used in the system login. The login username should be between 1 to 32 characters long.
• Password: The password is displaying the “x”. But the actual password was saved in the /etc/shadow file in an encrypted format.
• User ID (UID): The user id is 1004. The user having their user id. It is very important for user identification on the system level. By default, the UID or the user-id “0” is reserved for the root user.
• Group ID (GID): The group id is “1004”. The primary Group ID i.e. the GID. The GID information is store in the “/etc/group” file.
• User Info: Currently the user information is blank. as per the requirement, we can add the user info for further reference.
• Home Directory: The home directory path is “/home/test_user”. But as per the requirement, we can change the home directory path.
• Shell: The shell has provided to the user is “/bin/bash”. As per the requirement, we can provide different shell access.

Examples to implement Linux Add User command

Here are the following examples mention below:

Example #1 – Create New User

The “adduser” command is a very simple and common way to add or create a new user in a Linux environment.

Command :        

adduser demo_user

Explanation :

As per the above command, we are adding the “demo_user” with the help of the adduser command.

Output :

Screenshot 1 (a)

Screenshot 1 (b)

Example #2 – Specific User ID

By default, when we are creating a new user. The user ID will provide by the system on their own and it is in the sequential manager. But as per our requirement, we can provide the specific user ID also.

Command:

adduser -u 2000 demo_user1

Explanation :

As per the above command, we are adding the specific user ID for the “demo_user1” user. We are using the “-u” option to add the specific user id i.e. 2000.

Output :

Screenshot 2 (a)

Screenshot 2 (b)

Example #3 – Specific Group ID

In the adduser command, we can set our user ID. Similarly, we can also change the group ID as well.

Command :

useradd -u 2001 -g 10000 demo_user2

Explanation :

As per the above command, we are adding the specific group ID for the “demo_user5” user. We are using the “-g” option to add the specific group id i.e. 1000.

Output :

Example #4 – To Add the New User in Multiple Groups

In the Linux environment, we are having the functionality to add the new user in multiple exiting groups in a single shot.

Command :

useradd -G data_user,demo_user demo_user6

Explanation :

As per the above command, we are using the “-G” option in the useradd command. We are adding the “demo_user6” user to the “data_user,demo_user” group.

Output :

Screenshot 4 (a)

Screenshot 4 (b)

Example #5 – Add User without Home Directory

In the adduser command, we can add the new user without a home directory. The new user will store their data on the “root” location if they are having the proper permission and access.

Command :

adduser -M demo_user8

Explanation :

By default, the home directory will add to the newly created user. But in adduser command, we are having the facility to add the user without “home directory”. We have added the “demo_user8” without a home directory.

Output :

Example #6 – Add User with Account Expiry Date

In the adduser command, we can set the user account expiry date of the user.

Command :

useradd -e 2060-01-01 demo_user9
chage -l demo_user9

Explanation :

We have set the account to expire date“Jan 1, 2060” for the user “demo_user9” user. After the expiration date, the account will stop performing.

Output :

Conclusion – Linux Add User

We have seen the uncut concept of “Linux Adduser Command” with the proper example, explanation, and command with different outputs. The adduser command is used to add the new user to the Linux environment. We can add the user with proper configuration and user limitations.

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This is a guide to Linux Add User. Here we discuss how Linux Adduser Command works along with the commands and respective examples. You may also have a look at the following articles to learn more –

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