Linux delete user from group

10 practical examples to add or remove user from group in Linux

Table of Contents

In this article I will cover the below topics and share multiple practical examples cover these scenarios

• Different types of group in Linux
• Add user to group (single)
• Add user to multiple groups
• Change primary group of the user
• Remove user from group

So when you say Linux add user to group, which group do you mean? There are two types of group in Linux

• Primary Group
• Supplementary or Secondary Group

Difference between Primary vs Supplementary Group

Primary group:

• The group that is listed in the group membership field for a user in /etc/passwd .

For example here deepak is part of primary group with GID 1000 i.e. deepak (so primary group name is same as loginname)

• When we create user using useradd , depending upon USERGROUPS_ENAB variable in /etc/login.defs a primary group is created/assigned to user. If this variable is set to yes, a group will be created for the user, with the same name as her loginname . If the variable is set to no, useradd will set the primary group of the new user to the value specified by the GROUP variable in /etc/default/useradd , or 100 by default
• On Linux, every file and directory has a user owner and a group owner. Group ownership is set when files are created, and unless configured otherwise, it is set to the primary group of the user who creates the file.
• A user at a time can be part of only one primary group.

Supplementary (or Secondary) Group:

• A user can be part of multiple supplementary group
• A group that a user is a member of but which membership is not defined in the /etc/passwd file.
• When creating new files, the supplementary group will not automatically become the owner of those files.

1. Create a new user and add to existing primary group

• By default when we create a new user, a new primary group is created by the same name as of the user.
• But we can also use useradd to create a user and add this user to any existing group
• So this group will not become the primary group of your new user

In this example I will create a new group » admin «

Verify the group exists

Next I will create a new user » user1 » and add this user to » admin » group using useradd -g

Verify the primary group of user1

2. Create a new user and add to existing supplementary group

We want to create a new user and add him/her to supplementary group (please NOTE, we will add the user to supplementary group and not the primary group here)

I have below list of groups on my Linux server

I will create a new user » user2 » and add this user to all these supplementary groups using useradd -G , , ..

Verify the supplementary groups.

Please NOTE that since we did not specified primary group using -g , a new group user2 is created and assigned as primary group to the user

3. Create a new user and add to existing primary and supplementary group

Now we will combine both the above arguments i.e. -g to add primary_group and -G to add supplementary_group
In this example i will create user3 with primary_group as admin and with supplementary_group of devops and qa_team

Verify the new user group details

4. Change primary group of existing user

I have a user who is currently added to his own primary group

I will change the primary group of this user to admin using usermod

Verify the new primary group for user4

5. Add user to Group (Supplementary or Secondary) using usermod

• To add user to group we can use use usermod or gpasswd command
• We can add user to supplementary groups only
• In this example I will add user4 to devops supplementary group

Syntax to add user to group: usermod -G

Verify the user details

6. Add user to multiple groups (Supplementary or Secondary) using usermod

We can also add user to multiple supplementary groups using syntax usermod -G , , ..
In this example I will add user4 to multiple supplementary groups ( devops and qa_team )

Verify the user details

7. Add user to Group (Supplementary or Secondary) using gpasswd

• Similar to usermod we can also user gpasswd to add user to group
• The syntax to add user to group is gpasswd -M

In this example I will add user4 to devops as supplementary group

Verify the user details

Alternatively you can also user gpasswd -a

In this example I will add user4 to qa_team as supplementary group

Verify the user details

8. Add multiple users to same group

We need to user gpasswd to add multiple users to same group
Currently I already have admin group which does not contain any users at the moment

The syntax to add multiple users to single group would be gpasswd -M , , ..

In this example I will add my existing users i.e. user1 , user2 and user3 to admin as supplementary group

Verify the admin group details

9. Remove user from Group (Supplementary or Secondary)

Currently my user4 is part of three different supplementary groups

gpasswd is the best tool to remove user4 from qa_team group

We can also use usermod command to remove user from group. The problem with usermod is that you must define the complete list of supplementary group which the user is part of and only remove the group which you wat to remove the user from.

For example, my user4 is part of devops , admin and qa_team . So to remove user4 from qa_team we will re-add user to group devops and admin (not to qa_team )

Verify the user details

I would recommend using gpasswd to remove user from group

10. Remove multiple users from supplementary group

There is no single command to remove multiple users from single group but we can use a small script
Currently I have admin which has three users

I will write a small script to remove all the 3 users from admin group

remove multiple users from same group

11. Remove user from all Groups (Supplementary or Secondary)

• We can use gpasswd to remove user from group
• But if a user is part of multiple groups then you need to execute gpasswd multiple times
• Or write a script to remove user from all the supplementary groups
• Alternatively we can use usermod -G «»

Currently my user4 is part of multiple supplementary groups

To remove user from all supplementary groups, use:

Verify the user details

Lastly I hope the steps from the article to add user to group, remove user from group and difference between primary group and supplementary group on Linux was helpful. So, let me know your suggestions and feedback using the comment section.

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How to Add or Remove a User from a Group in Linux

Linux is by default a multi-user system (meaning many users can connect to it simultaneously and work), thus user management is one of the fundamental tasks of a system administrator. User management includes everything from creating, updating, and deleting user accounts or user groups on a Linux system.

In this short quick article, you will learn how to add or remove a user from a group in a Linux system.

Check a User Group in Linux

To check a user group, just run the following groups command and provide the username (tecmint in this example) as an argument.

To check your own groups, just run the groups command without any argument.

Check a User Group in Linux

Add a User to a Group in Linux

Before trying to add a user to a group, ensure that the user exists on the system. To add a user to a certain group, use the usermod command with the -a flag which tells the usermod to add a user to the supplementary group(s), and the -G option specifies the actual groups in the following format.

In this example, tecmint is the username and postgres is the group name:

Add User to Group in Linux

Remove a User from a Group in Linux

To remove a user from a group, use the gpasswd command with the -d option as follows.

Remove User from Group in Linux

Additionally, on Ubuntu and it’s derivative, you can remove a user from a specific group using the deluser command as follows (where tecmint is the username and postgres is the group name).

For more information, see the man pages for each of the different commands we have used in this article.

You will also find the following user management guides very useful:

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🐧 Как удалить пользователя Linux из группы

Пользователь может быть членом одной основной и одной или нескольких дополнительных групп в Linux.

Файл /etc/group определяет членство в группе для каждого пользователя в системе Linux.

В этом руководстве мы узнаем, как удалить пользователя из группы в Linux.

Мы будем использовать два метода, а также я покажу, как вручную удалить пользователя из группы, удалив содержимое из файла /etc/group.

Как создать пользователя Linux

Для целей данного руководства мы создадим пользователя с именем «testuser».

Когда создается новый пользователь, также создается новая основная группа с тем же именем для этого пользователя.

Мы создадим нового пользователя, введя следующую команду:

Теперь мы можем создать пароль для этого пользователя:

Добавление пользователя в группу

Сначала мы создадим две новые группы с помощью команды groupadd следующим образом:

Узнайте группы, к которым принадлежит пользователь

Мы также можем использовать два альтернативных способа проверить, к каким группам принадлежит пользователь, следующим образом:

Удаление пользователя из группы с помощью usermod

Мы можем удалить пользователя из группы или нескольких групп одновременно, используя команду usermod.

Используя usermod, вы должны указать, в каких вторичных группах вы хотите сохранить пользователя.

Позвольте мне объяснить на примере.

Чтобы удалить пользователя «testuser» из групп «testgroup1» и «testgroup2», выполните следующую команду (т.е. оставьте testuser только в группе «root» и его основной группе «testuser»):

Поэтому, чтобы удержать пользователя в большем количестве групп, вам нужно упомянуть имена групп, разделенные запятой (,), например:

Удаление пользователя из группы с помощью gpasswd

Другая команда, которая выполняет аналогичные результаты – это gpasswd.

Мы используем эту команду для удаления пользователей из указанных групп, в отличие от usermod.

Чтобы удалить пользователя из одной определенной группы, мы можем использовать команду gpasswd:

Удаление пользователя из группы (вручную)

Мы также можем удалить пользователя из группы, отредактировав файл ‘/etc/group’ вручную.

Эффекты этого метода будут применяться к пользователю после перезагрузки.

Вы можете использовать ваш любимый текстовый редактор для редактирования файла /etc/group:

Заключение

В этом уроке мы узнали, как удалить пользователя из группы с помощью usermod, gpasswd, а также вручную из файла /etc/group.

Эти инструкции можно использовать в любой системе Linux, такой как Ubuntu, CentOS, Fedora и многих других.

Если у вас есть какие-либо вопросы, пожалуйста, сообщите нам об этом в комментариях ниже.

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How to Remove Linux User from a Group

A user can be a member of one primary and one or several secondary (supplementary) groups in Linux. The file ‘/etc/group’ defines group membership for each user in the Linux system.

In this tutorial, we will learn how to remove a user from a group in Linux. We will use two methods and also I will show how to manually remove the user from the group by deleting from ‘/etc/group’ file.

Create Linux User

For the purpose of this tutorial, we will create a user named ‘testuser’. When a new user is created, a new primary group with the same name for that user is created too.

We will create a new user by issuing the following command:

Now we can create a password for that user:

I used the same password as the username so I got a warning that the password shouldn’t contain the user name in some form.

Adding a User to a Group

First, we will create two new groups using groupadd command as follows:

Now we will add ‘testuser’ user to the above created two groups and also add to ‘root’ group using the following commands:

Ok, so now if we look at ‘/etc/group’ file and can see that ‘testuser’ is a member of all three groups.

Find out the Groups a User belongs

We can also use two alternative ways to check to which groups does a user belong as follows

As you can see the output is very similar and those commands accomplish the same thing.

Removing User from a Group Using usermod

We can remove a user from a group or several groups at once using usermod command. Using usermod you have to specify in which secondary groups you want to keep the user in. Let me explain with an example.

In order to remove user ‘testuser’ from ‘testgroup1’ and ‘testgroup2’ group run the below command ( ie leave testuser only in ‘root’ group and it’s primary ‘testuser’ group):

So in order to keep a user in more groups, you’ll need to mention group names separated by comma (,) like:

Removing User from a Group Using gpasswd

Another command that accomplishes similar results is gpasswd. We use this command to remove users from specified groups, unlike with usermod.
To remove a user from one specific group we can use gpasswd command:

Removing User from a Group (Manually)

We can also remove a user from a group by manually editing the file ‘/etc/group’. The effects of this method will apply to the user upon reboot.

You can use your favourite text editor to edit the ‘/etc/group’ file:

We will now manually edit the last two entries to delete testuser and remove it from testgroup1 and testgroup2 (edited file should look like this):

Changes will take place after reboot, and now the user has been removed from those two groups:

Conclusion

In this tutorial, we have learned how to remove a user from a group using usermod, gpasswd and also by manually deleting them from ‘/etc/group’ file.

These instructions can be used on any Linux system like Ubuntu, CentOS, Fedora and many others. If you have any questions, please let us know in the comments below.

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