View all groups in linux

How can I display all users and groups with a command?

users and groups commands display users currently logged in, and groups a user belongs to respectively.

How to display a list of all users and all groups by command-line?

2 Answers 2

You can display with the help of compgen builtin command as follows:

To display all users run following command:

However you can also display all users by cut -d «:» -f 1 /etc/passwd .

Nice! it might be preferable to use getent passwd / getent group instead of cat’ing the local files ( getent should work for non-local accounts as well)

Well, on my ubuntu, I have some files created by docker mount with 999:999 as user:group , but unfortunately none of the above commands prints them.

Here we are going to use getent for the detailed the info

We can list the user with the following command:

We can list the group as follows:

To fetch detail a specific user

Replace the lalit with your user name. Lalit will not be in every system 🙂

You can read the more into about getent here

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How to List Groups in Linux

In Linux, a group is a collection of users. The main purpose of the groups is to define a set of privileges like read, write, or execute permission for a given resource that can be shared among the users within the group. Users can be added to an existing group to utilize the privileges it grants.

This tutorial explains how to show all groups a user is a member of. We will also explain how to list all members of a group.

Linux Groups #

There are two types of groups that a user can belong to:

• Primary or login group – is the group that is assigned to the files that are created by the user. Usually, the name of the primary group is the same as the name of the user. Each user must belong to exactly one primary group.
• Secondary or supplementary group — used to grant certain privileges to a set of users. A user can be a member of zero or more secondary groups.

List all Groups a User is a Member of #

There are multiple ways to find out the groups a user belongs to.

The primary user’s group is stored in the /etc/passwd file and the supplementary groups, if any, are listed in the /etc/group file.

One way to find the user’s groups is to list the contents of those files using cat , less or grep . Another easier option is to use a command whose purpose is to provide information about the system’s users and groups.

Using the groups command #

The most memorable command to list all groups a user is a member of is the groups command. When executed without an argument the command will print a list of all groups the currently logged in user belongs to:

The first group is the primary group.

john adm cdrom sudo dip plugdev lpadmin sambashare

To get a list of all groups a specific user belongs to, provide the username to the groups command as an argument:

Same as before the first group is the primary group.

Using the id command #

The id command prints information about the specified user and its groups. If the username is omitted it shows information for the current user.

For example to get information about the user linuxize you would type:

The command will show the user ID ( uid ), the user’s primary group ( gid ), and the user’s secondary groups ( groups )

uid=1001(linuxize) gid=1001(linuxize) groups=1001(linuxize),27(sudo) 

To print only the names instead of the numbers use the -n option. Option -g will print only the primary group and -G all groups.

The following command will print the names of the groups the current user is a member of:

john adm cdrom sudo dip plugdev lpadmin sambashare 

List All Members of a Group #

To list all members of a group, use the getent group command followed by the group name.

For example, to find out the members of a group with the name developers you would use the following command:

If the group exists the command will print the group and all its members:

If there is no output that means the group doesn’t exist.

List All Groups #

To view all groups present on the system simply open the /etc/group file. Each line in this file represents information for one group.

Another option is to use the getent command which displays entries from databases configured in /etc/nsswitch.conf file including the group database which we can use to query a list of all groups.

To get a list of all groups, type the following command:

The output is the same as when displaying the content of the /etc/group file. If you are using LDAP for user authentication the getent will display all groups from both /etc/group file and LDAP database.

You can also use awk or cut to print only the first field containing the name of the group:

Conclusion #

In this tutorial, you learned how to find the groups a user is a member of. The same commands apply for any Linux distribution, including Ubuntu, CentOS, RHEL, Debian and Linux Mint.

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

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How do I List All Groups in Linux

Linux systems may have several users that are divided into many groups. These groups are the collection of users with the same set of privileges like reading, writing, or executing permission for a particular file or resources shared among the users of that group. Linux allows you to add a new user or the existing user to the existing group for utilizing the privileges of that particular group that it will grant. We will learn about the various Linux groups and how to list all the members of the group.

Types of Groups in Linux

Linux has two types of groups that contain several users:

• Primary or Login Group: it is the group associated with the files created by a specific user. The name for that primary group has the same name as the user’s name that will create that specific file. Each user must belong to exactly a single group.
• Secondary or Supplementary Group: you can use this type of group to grant privileges to a set of users that belong to that group. A user can be assigned to no or more secondary groups.

Listing Users on Linux

For listing all the users present on the Linux system, you can run the cat command on the ‘/etc/passwd” file. This command will help in returning the number of users that are present on the Linux system.

Also, use the “less” or “more” command for navigating within the user’s list.

Listing Users Using the /etc/passwd File

For listing the usernames on the Linux system, you can use the “cat” command and then pipe the output to the “cut” command to isolate the usernames available in the first column in the list. Run the below-mentioned command as shown below.

Listing Usernames Using awk

For listing the usernames on the Linux system, use the “cat” command and then pipe the output to the “awk” command that works similar to the “cat” command.

Here we are using the “awk” interpreter, as shown below.

Listing Usernames Using getent

Use the getent command along with the “passwd” argument for listing the usernames available on Linux. Also, you can mention the optional user that you want to be displayed on the screen.

The getent command retrieves the entries from the Name Service Switch databases. It is a Unix utility for retrieving entries from various data sources. Check the list of the data sources available from the nsswitch.conf, which is stored at /etc.

If you want to list all the users with the help of the getent function, you can run the following command.

Listing the Connected Users on Your Linux Host

To get the list of the users connected to the Linux system, you can use the following command.

Using this command, you will provide the connected users’ list and the shell they are using.

Also, you can use the “users” command to get the same result as the “who” command, as shown below.

Listing Groups Using /etc/group File

Use the most commonly used “cat” command to get the list of the groups available in the “/etc/group” file. When you run the command, you will get the list of the groups.

But if you are looking for the group names that are present in the “/etc/group” file, use the cat command and then pipe the output to the “cut” command as shown below.

Also, if you want to isolate one group to check what users belong to that group, use the below command.

Listing Groups Using getent

You can use the “getent” command for listing the users on the Linux system.

If you do not provide the key, you will get the entire group file.

Listing Groups for the Current User

Using the “group” command will display a list of groups a specific user is in.

If you do not provide any argument, you will get the list of the groups for the user that runs the command.

Conclusion

The Linux system contains users and groups in different files. Sometimes it becomes important to get the user details and to which group they belong. Thus Linux offers some commands that will help you to achieve that. You can run some commands to get the user details and the group to which they belong. You can also get the complete list of users on the Linux system, active users, and groups names.

You can go through this article to get various commands for getting the list of all the groups in Linux and understand how they work.

About the author

Simran Kaur

Simran works as a technical writer. The graduate in MS Computer Science from the well known CS hub, aka Silicon Valley, is also an editor of the website. She enjoys writing about any tech topic, including programming, algorithms, cloud, data science, and AI. Travelling, sketching, and gardening are the hobbies that interest her.

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