How to Create Users in Linux (useradd Command)

Linux is a multi-user system, meaning that more than one person can interact with the same system simultaneously. If multiple people use one system, it is best to create a user account for each person to ensure their security and privacy.

There are two general types of users in Linux. The first type is regular users created by the administrator, and the second is system users created by the system and applications and used to run services. Based on their permission levels, regular users can be further classified as standard and administrative users. Granting administrative permissions should only be done when it is absolutely necessary and to users or services whom you trust.

As a system administrator, you are responsible for managing the system’s users and groups by creating and removing users , as well as assigning them to different groups .

In this article, we will explain how to create new user accounts using the useradd command.

useradd Command #

useradd is a command line utility that can be used to create new users in Linux and Unix systems.

The general syntax for the useradd command is as follows:

useradd [OPTIONS] USERNAME

Only root or users with sudo privileges can create new user accounts with useradd.

When invoked, useradd creates a new user account according to the options specified on the command line and the default values set in the /etc/default/useradd file.

The variables defined in this file differ from distribution to distribution, which causes the useradd command to produce different results on different systems.

useradd also reads the content of the /etc/login.defs file. This file contains configuration for the shadow password suite, such as password expiration policy, ranges of user IDs used when creating the system and regular users, and more.

How to Create a New User in Linux #

To create a new user account, invoke the useradd command followed by the name of the user.

For instance, to create a new user named jane, you would run the following:

sudo useradd jane

The command adds an entry to the /etc/passwd, /etc/shadow, /etc/group, and /etc/gshadow files.

You can verify that the user was created and view the user’s details by running the id command:

sudo id jane

uid=1005(jane) gid=1005(jane) groups=1005(jane)

To be able to log in as the newly created user, you need to set the user password. You can do that by running the passwd command followed by the username:

sudo passwd jane

The command will prompt you to enter and confirm the password. Make sure you use a strong password.

Changing password for user jane.
New password:
Retype new password:
passwd: all authentication tokens updated successfully.

How to Add a New User and Create Home Directory #

A home directory is a directory in a multi-user operating system that contains files of a particular user. It is also known as the login directory.

On most Linux distributions, when creating a new user account with useradd, the user’s home directory is not created.

Use the -m (--create-home) option to create the user home directory as /home/<username>:

sudo useradd -m jane

The command above creates the new user’s home directory and copies files from /etc/skel directory to the user’s home directory. If you list the files in the /home/jane directory, you will see the initialization files:

ls -la /home/jane/

total 20
drwxr-x--- 2 jane jane 4096 Dec 20 17:58 .
drwxr-xr-x 4 root root 4096 Dec 20 17:58 ..
-rw-r--r-- 1 jane jane  220 Jan  6  2022 .bash_logout
-rw-r--r-- 1 jane jane 3771 Jan  6  2022 .bashrc
-rw-r--r-- 1 jane jane  807 Jan  6  2022 .profile

The user has the ability to write, edit and delete files and directories within the home directory.

Creating a User with a Specific Home Directory #

By default, useradd creates the user’s home directory in /home. Use the d (--home) option to specify a different location.

Here’s an example of how to create a new user named jane with the home directory /opt/jane:

sudo useradd -m -d /opt/jane jane

Creating a User with a Specific User ID #

In Linux and Unix-like operating systems, users are identified by unique UID and username.

User identifier (UID) is a unique positive integer the Linux system assigns to each user. The UID and other access control policies are used to determine the types of actions a user can perform on system resources.

By default, when a new user is created, the system assigns the next available UID from the range of user IDs specified in the login.defs file.

Invoke the useradd command with the -u (--uid) option to create a user with a specific UID.

For instance, to create a new user named jane with a UID of 1500, you would type:

sudo useradd -u 1500 jane

You can verify the user’s UID, using the id command:

id -u jane

1500

Creating a User with a Specific Group ID #

Linux groups are organization units that are used to organize and administer user accounts in Linux. The primary purpose of groups is to define a set of privileges, such as reading, writing, or executing permission for a given resource that can be shared among the users within the group.

When creating a new user, the default behavior of the useradd command is to create a group with the same name as the username and the same GID as the UID.

The -g (--gid) option allows you to create a user with a specific initial login group. You can specify either the group name or the GID number. The group name or GID must already exist.

The following example shows how to create a new user named jane and set the login group to users:

sudo useradd -g users jane

To verify the user’s GID, use the id command:

id -gn jane

users

Creating a User and Assign Multiple Groups #

There are two types of groups in Linux operating systems: Primary and Secondary (or supplementary) groupss. Each user can belong to exactly one primary group and zero or more secondary groups.

You can use the -G (--groups) option to specify a list of additional (supplementary) groups for the user.

The following command creates a new user named john with primary group users and secondary groups wheel and docker.

sudo useradd -g users -G wheel,docker john

You can check the user groups by typing:

id john

uid=1002(john) gid=100(users) groups=100(users),10(wheel),993(docker)

Creating a User with a Specific Login Shell #

When a new user is created, its login shell is set to the one specified in the /etc/default/useradd file. In some distributions, the default shell is set to /bin/sh, while in others, it is set to /bin/bash.

The -s (--shell) option allows you to specify the new user’s login shell.

Here’s an example showing how to create a new user named john with /usr/bin/zsh as a login shell type:

sudo useradd -s /usr/bin/zsh john

Check the user entry in the /etc/passwd file to verify the user’s login shell:

grep john /etc/passwd

john:x :1001:1001::/home/john:/usr/bin/zsh

Creating a User with a Custom Comment #

The user’s full name or contact information can be added as a comment.

To add a short description for the new user use the -c (--comment) option.

In the following example, we are creating a new user named john with the text string “Test User Account” as a comment:

sudo useradd -c "Test User Account" john

The comment is saved in /etc/passwd file:

grep john /etc/passwd

john:x :1001:1001:Test User Account:/home/john:/bin/sh

The comment field is also known as GECOS.

Creating a User with an Expiry Date #

To define a time at which the new user accounts will expire, use the -e (--expiredate) option. This is useful for creating temporary accounts.

The date must be specified using the YYYY-MM-DD format.

For example, to create a new user account named john with an expiry time set to January 22, 2025 you would run the following:

sudo useradd -e 2025-01-22 john

Use the chage command to verify the user account expiry date:

sudo chage -l john

The output will look something like this:

Last password change					: Dec 11, 2023
Password expires					: never
Password inactive					: never
Account expires						: Jan 22, 2025
Minimum number of days between password change		: 0
Maximum number of days between password change		: 99999
Number of days of warning before password expires	: 7

Creating a System User #

System users are typically created during OS and package installations, and there is no real technical difference between them and regular users.

Use the -r (--system) option to create a system user account. For example, to create a new system user named john you would type:

sudo useradd -r john

System users are created with no expiry date. Their UIDs are chosen from the range of system user IDs specified in the login.defs file, which is different than the range used for regular users.

Changing the Default useradd Values #

The default useradd options can be viewed and changed using the -D, --defaults option or by manually editing the /etc/default/useradd file.

To view the current default options, type:

useradd -D

The output will look something like this:

GROUP=100
HOME=/home
INACTIVE=-1
EXPIRE=
SHELL=/bin/sh
SKEL=/etc/skel
CREATE_MAIL_SPOOL=no

Let’s say you want to change the default login shell from /bin/sh to /bin/bash. To do that, specify the new shell as shown below:

sudo useradd -D -s /bin/bash

You can verify that the default shell is changed by running the following command:

sudo useradd -D | grep -i shell

SHELL=/bin/bash

Conclusion #

We have shown you how to create new user accounts using the useradd command. The same instructions apply to all Linux distributions, including Ubuntu, CentOS, RHEL, Debian, Fedora, and Arch Linux.

adduser is a frendly interactive interface for useradd available on Debian-based systems.

Feel free to leave a comment if you have any questions.