Show all user groups linux

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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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 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 find out what group a given user has?

This appears to be pretty useful as well. It has more verbose output than the ‘groups’ command, so if you need the group id/user id use this!

On Linux/OS X/Unix to display the groups to which you (or the optionally specified user) belong, use:

which is equivalent to groups [user] utility which has been obsoleted on Unix.

On OS X/Unix, the command id -p [user] is suggested for normal interactive.

Explanation on the parameters:

-G , —groups — print all group IDs

-n , —name — print a name instead of a number, for -ugG

-p — Make the output human-readable.

or just study /etc/groups (ok this does probably not work if it uses pam with ldap)

Below is the script which is integrated into ansible and generating dashboard in CSV format.

sh collection.sh #!/bin/bash HOSTNAME=`hostname -s` for i in `cat /etc/passwd| grep -vE "nologin|shutd|hal|sync|root|false"|awk -F':' '' | sed 's/[[:space:]]/,/g'`; do groups $i; done|sed s/\:/\,/g|tr -d ' '|sed -e "s/^/$HOSTNAME,/"> /tmp/"$HOSTNAME"_inventory.txt sudo cat /etc/sudoers| grep -v "^#"|awk ''|grep -v Defaults|sed '/^$/d;s/[[:blank:]]//g'>/tmp/"$HOSTNAME"_sudo.txt paste -d , /tmp/"$HOSTNAME"_inventory.txt /tmp/"$HOSTNAME"_sudo.txt|sed 's/,[[:blank:]]*$//g' >/tmp/"$HOSTNAME"_inventory_users.txt 

My output stored in below text files.

cat /tmp/ANSIBLENODE_sudo.txt cat /tmp/ANSIBLENODE_inventory.txt cat /tmp/ANSIBLENODE_inventory_users.txt 

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