Find user groups linux

How to list all groups a user is a member of

Before delving into the 5 ways, let’s first understand some basics:

Adding a user to an existing group is one of the typical tasks of a Linux administrator.

A group is a collection of users. The main purpose of the group is to define a set of privileges to their members within the group.

It can be a difficult task if you want to assign a set of privileges to multiple users without a group. This is where the group comes in handy.

All system users are listed in the /etc/passwd file, the groups are listed in the /etc/group file, and the actual password is stored in the /etc/shadow file.

No matter what command we use, it will fetch information from these files.

There are two types of groups in Linux:

What is primary group?

The primary group is the main group associated with the user account. Each user must be a member of a single primary group.

What is secondary group?

The secondary or supplementary group is used to grant additional rights to the user. Each user can become a member of multiple secondary groups.

What is /etc/passwd file

“/etc/passwd” is a text file containing every user information that is required to login to the Linux system. It maintains useful information about users such as username, password, user ID, group ID, user information, home directory and shell.

Each user profile in the password file is a single line with seven fields as shown below:

$ grep "daygeek" /etc/passwd daygeek:x:1000:1000:daygeek. /home/daygeek:/bin/bash

What is /etc/group file

“/etc/group” is a text file that defines which groups a user belongs to. We can add multiple users in the same group.

Linux has three permission levels which define how users can access it. These levels are user, group and others, which controls a users access to other users’ files and folders.

/etc/group file maintains useful information about the group such as group name, group password, group ID (GIT) and membership list. Each group details is shown in a single line with four fields as shown in the ‘method #5’ listed below.

The following seven commands will help you find out which groups a user belongs to in Linux.

• groups: Show All Members of a Group.
• id: Print user and group information for the specified username.
• lid or libuser-lid: It display user’s groups or group’s users.
• getent: Get entries from Name Service Switch libraries.
• compgen: compgen is bash built-in command and it will show all available commands for the user.
• members: List members of a group.
• /etc/group file: Also, we can grep the corresponding user’s groups from the /etc/group file.

Now let’s delve into the 5 methods which can be used to find the list of groups a user is part of in Linux:

Method-1: Using groups command

The ‘groups’ command is widely used by Linux admin to list all groups a user is a member of. It prints the information of the given user’s primary and supplementary groups as shown below:

$ groups daygeek daygeek : daygeek adm cdrom sudo dip plugdev lpadmin sambashare

Run ‘groups’ command without any arguments to display the list of groups associated with the current user as shown below:

$ groups daygeek adm cdrom sudo dip plugdev lpadmin sambashare

Method-2: Using id command

The id command stands for identity. It prints real and effective user, group, and supplementary group information such as username, UID, group names and GUID as shown below:

$ id daygeek uid=1000(daygeek) gid=1000(daygeek) groups=1000(daygeek),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),118(lpadmin),128(sambashare)

Just run the ‘id’ command to view group information about the current user as shown below:

$ id uid=1000(daygeek) gid=1000(daygeek) groups=1000(daygeek),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),118(lpadmin),128(sambashare)

Method-3: Using lid command

The lid or libuser-lid command displays information about groups containing user name, which requires sudo privileges.

You should run the libuser-lid command instead of the lid on newer systems.

$ sudo libuser-lid daygeek adm(gid=4) cdrom(gid=24) sudo(gid=27) dip(gid=30) plugdev(gid=46) lpadmin(gid=116) daygeek(gid=1000) sambashare(gid=126)

Method-4: Using the getent command

The getent command displays entries from databases supported by the Name Service Switch libraries, which are configured in ‘/etc/nsswitch.conf’:

$ getent group | grep daygeek adm:x:4:syslog,daygeek cdrom:x:24:daygeek sudo:x:27:daygeek,2gadmin dip:x:30:daygeek plugdev:x:46:daygeek lpadmin:x:116:daygeek daygeek:x:1000: sambashare:x:126:daygeek

The above command shows the group name and all other members associated with that group. Use the below customized command format to print only groups for a given user:

$ getent group | grep daygeek | awk -F: '' adm cdrom sudo dip plugdev lpadmin daygeek sambashare

Run the below command to print only the primary group information of the user:

$ getent group daygeek daygeek:x:1000:

Method-5: Using the ‘/etc/group’ file

User groups information can be filtered from the ‘/etc/group’ file using grep command as shown below:

$ grep daygeek /etc/group adm:x:4:syslog,daygeek cdrom:x:24:daygeek sudo:x:27:daygeek,2gadmin dip:x:30:daygeek plugdev:x:46:daygeek lpadmin:x:116:daygeek daygeek:x:1000: sambashare:x:126:daygeek

Use the below customized command format to print only groups for a given user:

$ grep daygeek /etc/group | awk -F: '' adm cdrom sudo dip plugdev lpadmin daygeek sambashare

Bonus Tip-1: Find out all groups using compgen command

Compgen is a bash built-in command that displays all groups in the Linux system:

$ compgen -g root daemon bin sys adm . . daygeek thanu renu sudha admin u1 u2

Bonus Tip-2: Listing members of a group using member command

The member command allows you to list members of a group in Linux:

$ members sudo daygeek 2gadmin

Closing Notes

In this guide, we have shown you several commands to list all groups a user is a member of in Linux.

If you have any questions or feedback, feel free to comment below.

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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]. .

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