List all user and groups 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 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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How to List Users and Groups in Linux, With Examples

Linux supports multiple users and groups, allowing access to be granted to only the resources required. Here’s how to list users, groups, and group membership.

Separating users and groups ensures that different people can’t accidentally interfere with each other’s files and ensures system security by denying access to vital system files.

This article details the various ways to query the users and groups on a computer running a Linux Operating System.

Listing All Users

The /etc/passwd file is a text-file database containing information on all of the users on a Linux system.

It can be viewed using the less command, which outputs a text file’s contents in a paginated manner (The list of users can be quite long).

You can also use the getent command to query the users database for your system:

getent is a tool specifically for querying various text-file databases used in the configuration of a Linux system.

The output of the above will look something like this:

pulse:x:123:128:PulseAudio daemon. /var/run/pulse:/usr/sbin/nologin gnome-initial-setup:x:124:65534::/run/gnome-initial-setup/:/bin/false gdm:x:125:130:Gnome Display Manager:/var/lib/gdm3:/bin/false linuxscrew:x:1000:1000:LinuxScrew. /home/linuxscrew:/bin/bash

You will see your user, along with a list of other users on the system – many applications and services will have their own user so that they can be granted permissions only to the system resources they require to operate, maintaining system functionality and security.

Each line in the /etc/passwd file holds the details of a single user. There are several fields, each separated by a : (colon). The values are as follows:

Value/Position	Meaning
1	The username for the user.
2	The password for the user. Usually, blank (noted by an x) as passwords are usually stored in an encrypted format in the /etc/shadow file.
3	UID (User ID) – the unique numerical identifier for the user.
4	GID (Primary Group ID) – the ID for the Primary group for the user (see below for more details). Group information is stored in the /etc/group file.
5	User Info. This field stores extra information about the user, like their full name or contact details, in a comma-separated format.
6	The users home directory – the path to the directory the user is placed in after login. For normal users, the user should have full permissions for this directory – it’s where they will store their files.
7	The path to the command line shell the user will use to operate the system. Usually, this is the path to the Bash shell, but there are other shells too. Some users do not require shell access and may have it set to /bin/false or /usr/sbin/nologin.

Listing Normal Users Only

To view only normal users – that is, users that you have created to log in and operate the computer (as opposed to users created for an application or service), run the following:

eval getent passwd <$(awk '/^UID_MIN/ ' https://cd.linuxscrew.com/etc/login.defs)..$(awk '/^UID_MAX/ ' https://cd.linuxscrew.com/etc/login.defs)>

A lot is going on here. Here’s a breakdown:

• eval is a command which will concatenate parameters following it into a single command and execute it
• gentent passwd queries the /etc/passwd file
• awk is a tool for searching for values in text
  • Here it’s first used to search the /etc/login.defs file to find out the range of numerical IDs which are assigned to normal users 0 defined by the UID_MIN and UID_MAX values in that file
  • It is then used to search the output from getent passwd for only users who have an ID in the above range.

  As this lists only normal users, the output is limited to the below on my machine:

  linuxscrew:x:1000:1000:LinuxScrew. /home/linuxscrew:/bin/bash

  Listing All Groups (And Their Members)

  The /etc/group file is (also) a text-file database containing information on all of the groups on a Linux system.

  Like the /etc/passwd file, it can be viewed using the less command, which outputs a text file’s contents in a paginated manner (the list of groups can be quite long).

  You can also use the getent command to query the groups database for your system:

  The output to both of the above will look something like this:

  colord:x:126: geoclue:x:127: pulse:x:128: pulse-access:x:129: gdm:x:130: lxd:x:131:linuxscrew linuxscrew:x:1000:

  As you can see, there are a lot of groups. Many applications and services will have their own unique group so that that service can be granted permission only to access the resources it needs – maintaining system stability and security.

  Each line in the /etc/group file represents a single group, with several information fields separated by a : (colon). The values are as follows:

  Value/Position	Meaning
  1	The name of the group
  2	Password for group. Generally not used (noted by a value of x). Can be set to enable privileged groups.
  3	GID (Group ID) – the unique numerical identifier of the group. If the group is the primary group for a user, the GID for the group will appear in the /etc/passwd file.
  4	The list of usernames for the users who are members of the group (unless it’s the users primary group – see below). Usernames are comma-separated.

  Primary and Secondary Groups

  Each user will have a single primary group and can also be a member of multiple secondary groups.

  Usually, the primary group shares its name with the user and is the default group given permissions to a file created by the user.

  The users primary group may not appear in the /etc/group file! It is usually defined in the /etc/passwd file in the GID (Group ID) field.

  Listing Groups of a Specific User

  To find out what groups you, the current user, are a member of, use the groups command

  The groups you are a member of will be listed, separated by spaces.

  To find out what groups another user is a member of, run:

  …where USERNAME is the name of the user you wish to list the groups for. You may need to run this as root or using the sudo command depending on your user permissions.

  The ‘id’ Command

  There is also the id command – it prints out the information for a user. To find information on the current user, run it:

  Or, to find information on another user, run:

  The UID (User ID), GID (Primary Group ID), and a list of all of the groups the user is a member of in the format GID(group name) will be output. It will look something like this:

  uid=1000(linuxscrew) gid=1000(linuxscrew) groups=1000(linuxscrew),27(sudo)

  Check out our other Linux Tips and Bash/Shell tutorials!

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