Linux List Users/Members in Group Commands & Syntax

In Linux, there is number of users and groups in the system who use and operate the system. The group is nothing but a logical mechanism to manage a collection of users.

There are two types of groups in Linux:,

  1. Primary Group
  2. Secondary Group

The Primary group is the main group that the operating system assigns to files that are created by the user. Each user must belong to a primary group.

The Secondary group is any group other than your primary group. Users can belong to up to 15 secondary groups.

If you are a Linux system administrator then it is an essential part of you to find how to list users of a specific group.

In this tutorial, we will show you how to find and list all members of a group in Linux.

Basic Syntax of Groups Command

The basic syntax of groups command is shown below:

groups [OPTION]... [USERNAME]...

You can display all the groups available in your system with the following command:

groups

You should get the following output:

vyom adm cdrom sudo dip plugdev lpadmin sambashare vboxusers chrome-remote-desktop

List All Groups Available in Your System

The simple and easiest way to list all the group available in your system with the following command:

cat /etc/group

You should see the following output:

root:x:0:
daemon:x:1:
bin:x:2:
sys:x:3:
adm:x:4:syslog,vyom
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:vyom,user1,user2
floppy:x:25:
tape:x:26:
sudo:x:27:vyom
audio:x:29:pulse
dip:x:30:vyom
www-data:x:33:
backup:x:34:
operator:x:37:
list:x:38:
irc:x:39:
src:x:40:
gnats:x:41:
shadow:x:42:
utmp:x:43:
video:x:44:
sasl:x:45:
plugdev:x:46:vyom
staff:x:50:
games:x:60:
users:x:100:
nogroup:x:65534:
libuuid:x:101:
netdev:x:102:
crontab:x:103:
syslog:x:104:
fuse:x:105:
messagebus:x:106:
ssl-cert:x:107:postgres
lpadmin:x:108:vyom
scanner:x:109:saned
mlocate:x:110:
ssh:x:111:
utempter:x:112:
avahi-autoipd:x:113:
rtkit:x:114:
saned:x:115:
whoopsie:x:116:
avahi:x:117:
lightdm:x:118:
nopasswdlogin:x:119:
bluetooth:x:120:
colord:x:121:
pulse:x:122:
pulse-access:x:123:
vyom:x:1000:
sambashare:x:124:vyom
vboxusers:x:125:vyom
postgres:x:126:
docker:x:999:
mysql:x:127:
chrome-remote-desktop:x:128:vyom
snmp:x:129:
user1:x:1001:
user2:x:1002:

You can also see the sample output in the following screen:

You can list all available groups with the following commands:

getent group

Or

more /etc/group

Or

less /etc/group

List all Members of a Group with Command Line

There are several ways you can list all members of a specific group. In this section, we will show you different methods to find all members of a group.

List all Members of a Group with the /etc/group File

The /etc/group is a file that contains information about all groups. You can use cat with grep command as shown below:

cat /etc/group | grep -i groupname

For example, if you want to list all members of a group named cdrom, run the following command:

cat /etc/group | grep -i cdrom

You should see the following output:

cdrom:x:24:vyom,user1,user2

You can also list all members of a group named cdrom using the awk command as shown below:

awk -F':' '/cdrom/{print $4}' /etc/group

You should see the following output:

vyom,user1,user2

You can also see the sample output in the following screen:

List all Members of a Group with members Command

You can also print all members of a group with members command. By default, members command is not installed in most Linux operating systems. You can install it by running the following command:

apt-get install members -y

After installing members package, you can all members of a specific group with the following command:

members groupname

For example, to display all the members of a group named cdrom run the following command:

members cdrom

You should see the following output:

vyom user1 user2

List all Members of a Group with lid Command

lid is an another command-line utility that can be used to provide information about groups containing usernames.

By default, lid utility is not installed in most Linux operating systems. You can install it by just running the following command:

apt-get install libuser -y

Once installed, you can display all users in the group named cdrom with the following command:

lid -g cdrom

You should see the following output:


vyom(uid=1000)
user1(uid=1001)
user2(uid=1002)

With lid command, you can also see the information of all groups that contain user named vyom as shown below:

lid vyom

You should see the following output:

adm(gid=4)
cdrom(gid=24)
sudo(gid=27)
dip(gid=30)
plugdev(gid=46)
lpadmin(gid=108)
vyom(gid=1000)
sambashare(gid=124)
vboxusers(gid=125)
chrome-remote-desktop(gid=128)

You can also see the sample output in the following screen:

Conclusion

In the above tutorial, we learned how to find and list all users of a specific group in Linux. We have also learned different commands to find all the members of a group with examples. I hope you have now enough knowledge to use these commands in the production environment.

Leave a Reply

Your email address will not be published. Required fields are marked *