Listing all 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 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 User Groups on Ubuntu Linux with examples

This brief tutorial shows students and new users how to list groups on Ubuntu 18.04 | 16.04 Linux systems.

If you’re a student or new user looking for a Linux system to start learning on, the most accessible place to start is on Ubuntu Linux OS. It’s a great Linux operating system for beginners.

Ubuntu is an open-source Linux operating system that runs on desktops, laptops, servers, and other devices.

Ubuntu and Windows systems allow you to be productive, easy to use, and reliable and enable you to install and run thousands of programs from gaming to productivity suite software for individuals and businesses.

This post shows you how to perform the primary task of listing groups on Ubuntu Linux.

Linux Groups:

There are two types of groups users can be assigned to. One is a primary, and the other is a second group that grants privileges to users to access specific resources.

Below is how a typical Linux user account is added and assigned group memberships:

User — A user with an account must belong to one primary group. The user’s primary group is typically named after the user account name.
Primary Group — The primary group is created simultaneously when the user account is created, and the user is automatically added to it. The file created by the user automatically belongs to the user group.
Secondary Group — This group is not required and is only there to give users access to other resources they don’t already have access to. Users can belong to one or as many secondary groups are possible.

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.

List User Groups using the group’s command

Now that you know the types of groups for users, you can use the groups command to find the groups a user belongs to. Running the groups command without arguments will list all the groups the user belongs to.

Should output all the groups the account richard belongs to. The primary group is the first group with the same name as the user account name.

Ouput: richard adm cdrom sudo dip plugdev lpadmin sambashare

To list all the groups a user belongs, add the username to the group’s command

This should output the same as above

Output richard : richard adm cdrom sudo dip plugdev lpadmin sambashare

List User Groups using the id command

One can also use the id command to list group information about the specified user. It prints user and group information for the specified USER,

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

Should output the line below:

Output: uid=1000(richard) gid=1000(richard) groups=1000(richard),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),116(lpadmin),126(sambashare)

List Group Membership using the getent command

If you want to know a particular group’s members, use the getent command. This command gets entries from the administrative database.

To get a membership of the cdrom group, run the command below

This should output all the users who have access to the cdrom group.

Listing All Groups

To list the entire groups on Ubuntu, run the command below

That should output all the groups on each line

root:x:0: daemon:x:1: bin:x:2: sys:x:3: adm:x:4:syslog,richard tty:x:5: disk:x:6: lp:x:7: mail:x:8: news:x:9: uucp:x:10: man:x:12: proxy:x:13: kmem:x:15: dialout:x:20: fax:x:21: voice:x:22: cdrom:x:24:richard floppy:x:25: tape:x:26: sudo:x:27:richard audio:x:29:pulse dip:x:30:richard .

Congratulations! You have learned how to list groups on Ubuntu Linux.

Richard W

I love computers; maybe way too much. What I learned I try to share at geekrewind.com.

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How to List All Groups in Linux?

Linux groups are a collection of users. They are meant to easily provide privileges to a group of users. In this tutorial, we will look at various ways to list all groups in Linux.

2 Ways to List All Groups in Linux

1. /etc/group file

The /etc/group file contains all the local groups. So, we can open this file and look at all the groups.

root@localhost:~# cat /etc/group root:x:0: daemon:x:1: bin:x:2: sys:x:3: adm:x:4:syslog tty:x:5: disk:x:6: lp:x:7: mail:x:8: news:x:9: .

If you are looking for a specific group, then use the grep command to filter it out.

root@localhost:~# cat /etc/group | grep sudo sudo:x:27:journaldev,test root@localhost:~#

2. getent command

Linux getent command fetch entries from databases supported by the Name Service Switch libraries. We can use it to get all the groups information from the group database.

root@localhost:~# getent group root:x:0: daemon:x:1: bin:x:2: sys:x:3: adm:x:4:syslog tty:x:5: .

Let’s look at some more examples of listing all the groups in Linux.

Linux List All Group Names

We can use cut command to print only the group names. This is useful when we are looking for a specific group name presence in a shell script.

root@localhost:~# cut -d: -f1 /etc/group root daemon bin sys adm tty .

We can use cut command with the getent command too.

root@localhost:~# getent group | cut -d: -f1 root daemon bin sys adm tty disk .

The cut command is splitting every line using the colon (:) delimiter. Then the first field, which is the group name, is selected using the -f1 option.

Listing All Group Names in Alphabetical Order

The above commands output can be passed to the sort command to print the output in natural sorting order.

root@localhost:~# getent group | cut -d: -f1 | sort adm audio backup bin cdrom crontab daemon .

Count of All the Linux Groups

If you are interested in the count of the linux groups, use the following commands.

root@localhost:~# cat /etc/group | grep -c "" 68 root@localhost:~# getent group | grep -c "" 68 root@localhost:~#

List All Groups of a User

We can use the groups command to get all the groups of a user.

root@localhost:~# groups journaldev journaldev : journaldev sudo test_users test_users_pwd root@localhost:~# root@localhost:~# groups root root : root root@localhost:~#

List Groups of the Current User

If you run the groups command without any user input, it will print the groups of the current user.

root@localhost:~# groups root root@localhost:~# su - journaldev journaldev@localhost:~$ groups journaldev sudo test_users test_users_pwd journaldev@localhost:~$

List User Groups Along with Group ID

We can use id command to print the user information. This command lists all the groups along with their group id.

root@localhost:~# id journaldev uid=1002(journaldev) gid=1003(journaldev) groups=1003(journaldev),27(sudo),1004(test_users),1007(test_users_pwd) root@localhost:~# root@localhost:~# id root uid=0(root) gid=0(root) groups=0(root) root@localhost:~#

List All Users of a Group

We can use the getent command or the /etc/groups file to get all the users that belongs to a group.

root@localhost:~# getent group sudo sudo:x:27:journaldev,test root@localhost:~# root@localhost:~# getent group sudo | cut -d: -f4 journaldev,test root@localhost:~#

Conclusion

The getent command and /etc/group file can be used to get all the Linux groups details. We can use them alongside cut and sort command to present the output in a better way.

References

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