What groups exist linux

7 methods to list user groups in Linux? [SOLVED]

In operating systems, applications add their own users and groups to the system. From an administrative point of view, this makes it easier for users. Adding users to the application group is the easiest way to edit privileges. As a matter of fact, systems such as LDAP and Active Directory are also built on this method.

There are many methods of listing groups in Linux. In some methods, group information is accessed from the user, while in some methods, users are accessed from group information. We will tell you some of the most used methods with examples.

Method-1: Using groups command

When you run the groups command without any parameters, it lists the group information of the user who opened the terminal:

foc@fedora:~$ groups foc wheel

If you type a username after the group command, the groups belonging to that user are listed:

foc@fedora:~$ groups golinux golinux : golinux

In this method, groups are listed with user information.

Method-2: Using id command

Like the group command, the id command, when executed without parameters, lists the active user’s groups. But this time group id are also displayed:

foc@fedora:~$ id uid=1000(foc) gid=1000(foc) groups=1000(foc),10(wheel)

By typing the username after the id command, the groups belonging to that user are listed with their ids:

foc@fedora:~$ id golinux uid=1001(golinux) gid=1001(golinux) groups=1001(golinux)

As the user’s group information increases, the information displayed on the screen may not be understood. With the parameters of the ID command, the output can be made more understandable. For example, to list all group ids and names:

foc@fedora:~$ id -Gn golinux golinux

You can get help from the —help page for all its parameters:

foc@fedora:~$ id --help Usage: id [OPTION]. [USER]. Print user and group information for each specified USER, or (when USER omitted) for the current user. -a ignore, for compatibility with other versions -Z, --context print only the security context of the process -g, --group print only the effective group ID -G, --groups print all group IDs -n, --name print a name instead of a number, for -ugG -r, --real print the real ID instead of the effective ID, with -ugG -u, --user print only the effective user ID

Again in this method, groups are listed with their user information.

Method-3: Using getent command

The getent command pulls information from the group database. If there is no central system such as LDAP, Active Directory, it will pull from the local database.

You can pull groups by typing group after getent command:

foc@fedora:~$ getent group root:x:0: bin:x:1: . disk:x:6: lp:x:7: mem:x:8: kmem:x:9: wheel:x:10:foc cdrom:x:11: mail:x:12:

To list users in a group, you must type the group name:

foc@fedora:~$ getent group wheel wheel:x:10:foc

To list all groups in the system without details:

foc@fedora:~$ getent group | cut -d: -f1 root bin disk lp mem kmem wheel cdrom mail 

This method lists both groups and users in that group.

Method-4: Using /etc/group file

On Linux the group information is in the /etc/group file. If a user is added or removed from the group, this file changes.

When you view this file with file view commands like cat , it gives a complex output. To list group information, you can write it like this:

foc@fedora:~$ cut -d: -f1 /etc/group root bin . lp mem kmem wheel . tape video ftp 

For the total number of groups:

foc@fedora:~$ cat /etc/group | grep -c "" 82

Using awk command we can extract the group names from the /etc/group file using the colon ( : ) delimiter.

Method-5: Using compgen command

Another command you can use to list groups in Linux is compgen . You can list the groups in the system with the -g parameter:

[foc@rocky9 ~]$ compgen -g root bin wheel ftp lock audio users nobody foc 

Method-6: Using lid command

This command displays information about the specified group, including the GID, group password (if any), and members.

# lid -g nagios nagios(uid=1001) apache(uid=48) snmptt(uid=974)

Method-7: Using dscl command (On MacOS)

Using the dscl command on macOS. This command displays information about the specified group on macOS.

dscl . -read /Groups/groupname

Bonus Tip

If you want to list the groups of users logged into the system, you can use the following for loop:

[foc@rocky9 ~]$ for user in $(cat /etc/passwd | grep bash | awk -F: '');do groups $user; done root : root foc : foc wheel

Note: Bash was chosen as the default shell. If a different shell(zsh,sh etc) is used, it can be written after the grep command.

What is NEXT?

Summary

There is always an alternative on Linux. We have explained different ways to list groups in Linux for you. The commands and methods used may vary according to habits. You can use whichever method is faster and easier for you. Of course the choice is yours.

You can get help with the -h/—help parameter for each command. For more detailed information, you can also access the man page of the commands as in the example:

foc@fedora:~$ man id NAME id - print real and effective user and group IDs SYNOPSIS id [OPTION]. [USER]. .

References

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How to List All Existing Groups in Linux System

Being able to manage users and groups in a Linux operating system environment is an important milestone in terms of Linux administration and security. Under Linux, each user account is automatically associated with a single primary group. A Linux user cannot be a member of two or more primary groups, only one.

However, when it comes to secondary groups, it’s a different case. A single Linux user account can be associated with more than one secondary group (up to 15).

In summary, a primary group is OS-assigned to each Linux user account and is linked to user-created files whereas secondary groups can be associated with multiple Linux user accounts and are not always automatically assigned.

This article will walk us through viable approaches to listing all existing groups within a Linux operating system distribution.

1. Reading the /etc/group File

By default, all defined groups in Linux are listed inside the /etc/group file. The entries in this file are represented in the following format:

group_name:password:GID:group_members

All the password entries are encrypted and GID stands for Group ID.

The entries in the /etc/group file are in plain text making it easier to output its content via a simple cat command.

We can therefore list all groups stored inside the /etc/group file in the following manner:

The above command outputs all groups present in a Linux system as the first column entry followed by the password, GID, and group_members fields if any.

What if we only wanted to output the group_name field? To achieve this objective, we will implement and use the cut command to only extract and output the group_name field from the /etc/group file entries.

• -d tells the cut command to use field delimiters as TABs replacement.
• -f1 tells the cut command to print the content of the first field (field 1) inside the /etc/group file.

2. Using getent Command

As per its manual page, the getent command is effective in accessing Name Service Switch libraries’ entries. The entries in the /etc/group file are supported by databases easily read by the getent command.

The getent command’s reference syntax is as follows:

$ getent [option]. database key.

In our case, its implementation in listing all groups in Linux is straightforward and simple as depicted below:

The first entry in each line represents the group names.

Listing All Groups of a Specific User in Linux

We can now comfortably identify and audit the existence of all groups in our Linux OS environment. What if we wanted to list all groups associated with a particular Linux user?

For the currently logged-in user, all you need to do is execute the following single command:

If you want to audit the groups assigned to other Linux users on the system, reference the following syntax:

For example, we can implement the above command syntax in the following manner:

Have any other ideas on listing all groups in Linux? Feel free to leave a comment or feedback.

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How to List All User Groups on Linux

Get better at user management by learning more about the existing user groups on your Linux computer.

Readers like you help support MUO. When you make a purchase using links on our site, we may earn an affiliate commission. Read More.

User groups on Linux help you define a set of permissions that you can then impose on other users. Unix and Linux come with some pre-configured user groups, and as an administrator, it’s easy to create additional groups to further categorize and manage users.

But before creating a new group, you’d want to know more about the existing ones. Luckily, there are several ways to list all user groups present on Linux, and you can even view the list of groups a specific user is a part of. Let’s get started.

Using the /etc/group File

The /etc/group file contains information on all local user groups configured on a Linux machine. With the /etc/group file, you can view group names, passwords, group IDs, and members associated with each group.

View the contents of the file using the cat command:

The output might be confusing at first. Where are the group names? And what are these «x»s and colons in the output?

The first column (the text before the first colon) is what you’re looking for. You can view a prettified version of the file and display only the group names using the cut command:

This simple list is both easier on the eyes and perfect for use in scripts.

You can also count the total number of local groups on your machine using wc:

To make things interesting, create a new group using the groupadd command and then view the total number of user groups on your system. As obvious, the count will increase by one and you’ll be able to see the group name listed in the output.

List Groups Using the getent Command

getent, short for «get entries,» is a Linux command for viewing the contents of system information files, also known as databases, on Linux. /etc/group, /etc/passwd, and /etc/shadow files are good examples of such databases.

Using the getent command to view user group information on Linux is straightforward. All you need to do is type getent followed by the file you want to view. In this case, it’s the group file.

The output of «getent group» will be slightly different from the cat /etc/group command. This is because getent pulls group information from other similar databases on your system (LDAP, for example).

Use the cut command to parse the output and display only group names:

The getent command is versatile. You can list the names of all users on Linux by getting all the entries from the /etc/passwd file and then parsing the output for user names.

View Group List for a Specific User Using groups

It’s hard to visually match user names with their groups using the previous methods. If you only want to list groups a particular user is a part of, consider using the groups command instead.

The basic syntax for the command is:

If you don’t specify a username, the output will display all groups for the current user. But for the sake of clarity, it’s best to supply a username as an argument.

To get a list of groups for a user named «testuser», run:

Groups Simplify User Access Control on Linux

Technically, the root user is the owner of the entire system and has permissions no other user possesses. Groups are a way for the superuser to categorize users, grant them authorizations, and impose restrictions to prevent them from performing undesirable operations.

Instead of granting permissions to each user, you can create a group and add all the users to it. Then, all you need to do is manage the permissions for the said group and the rules will be imposed upon the members automatically. This is one of the many ways to manage users on Linux and other Unix-related operating systems.

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