Linux see users in group

How to list all users in a Linux group?

I’m new here, I found out that SF exists right after I posted the question. I agree it belongs either to SF or SO.

20 Answers 20

It is portable across both Linux and Solaris, and it works with local group/password files, NIS, and LDAP configurations.

Unfortunately, there is no good, portable way to do this that I know of. If you attempt to parse /etc/group, as others are suggesting, you will miss users who have that group as their primary group and anyone who has been added to that group via a mechanism other than UNIX flat files (i.e. LDAP, NIS, pam-pgsql, etc.).

If I absolutely had to do this myself, I’d probably do it in reverse: use id to get the groups of every user on the system (which will pull all sources visible to NSS), and use Perl or something similar to maintain a hash table for each group discovered noting the membership of that user.

Edit: Of course, this leaves you with a similar problem: how to get a list of every user on the system. Since my location uses only flat files and LDAP, I can just get a list from both locations, but that may or may not be true for your environment.

Edit 2: Someone in passing reminded me that getent passwd will return a list of all users on the system including ones from LDAP/NIS/etc., but getent group still will still miss users that are members only via the default group entry, so that inspired me to write this quick hack.

 #!/usr/bin/perl -T # # Lists members of all groups, or optionally just the group # specified on the command line # # Copyright © 2010-2013 by Zed Pobre (zed@debian.org or zed@resonant.org) # # Permission to use, copy, modify, and/or distribute this software for any # purpose with or without fee is hereby granted, provided that the above # copyright notice and this permission notice appear in all copies. # use strict; use warnings; $ENV = "/usr/bin:/bin"; my $wantedgroup = shift; my %groupmembers; my $usertext = `getent passwd`; my @users = $usertext =~ /^([a-zA-Z0-9_-]+):/gm; foreach my $userid (@users) < my $usergrouptext = `id -Gn $userid`; my @grouplist = split(' ',$usergrouptext); foreach my $group (@grouplist) < $groupmembers-> = 1; > > if($wantedgroup) < print_group_members($wantedgroup); >else < foreach my $group (sort keys %groupmembers) < print "Group ",$group," has the following members:\n"; print_group_members($group); print "\n"; >> sub print_group_members < my ($group) = @_; return unless $group; foreach my $member (sort keys %<$groupmembers>) < print $member,"\n"; >> 

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How to List All Users of a Group in Linux

Wondering which users are members of a specific group? This tutorial shows you three simple ways to list all the users of a group in Linux command line.

I have already shown you to list all the users in Linux command line. This quick tip is related and yet different from that.

I presume that you are a bit familiar with the concept of groups and users in Linux. There are several groups and a variety of users in a Linux system. A group can have multiple members while a user can be a member of several groups.

You can check which groups a particular user belongs to and you can also find all the users of a group.

List all users of a group in Linux

In this quick tutorial, I’ll show you different ways to list users in a group in Linux command line.

1. List members of a group in Linux using /etc/group file

The group information is contained in the file /etc/group. You can view the content of this file and look for the information about the members.

Normally, this file has entry in the following format:

Here’s the explanation of the fields:

• adm is the group name
• x represents password field (you won’t see password in clear text of course)
• 4 is the Group ID aka GID
• syslog and abhishek are the users belonging to the group adm

If you find manual searching for a group in the file difficult, you can use a combination of the grep command and the cut command.

grep '^group_name:.*$' /etc/group | cut -d: -f4

The above command looks for all the lines starting with the specified group name and then the cut command extract the fourth column separated with : delimiter. The result is just the name of the group members.

grep '^adm:.*$' /etc/group | cut -d: -f4 syslog,abhishek

2. List group members in Linux with getent command

getent is a multipurpose command that is used to query from database files in the /etc directory. So you can use it to query the /etc/group file and get the users of the specified group in the following manner:

This will display the line matching the group name and in here you can see the members of the group:

getent group sudo sudo:x:27:abhishek

3. List users in a group using ‘members’ command

There is a tiny command line tool that simplifies the process of listing all the members of a specific group.

The members command is usually not installed in all the systems so you have to install it on your own.

On Debian/Ubuntu based systems, you can install it using the following command:

If the command is not found in Ubuntu, you should enable the universe repository and try it again.

Once you have the command installed, you can run it like this:

For example, if you want to check which users have sudo access, you can use the members command like this:

And the output will list all the users of the sudo group.

See, it was absolutely simple to get the users belonging to a group. You learned three ways to do it.

Which method did you like the most? Or, do you use some other way to list group members in Linux? Why not share it with us 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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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:,

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:

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

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:

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:

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:

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

You should see the following output:

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:

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

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

You should see the following output:

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:

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

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:

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.

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