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How can I find out which users are in a group within Linux?

I’ve recently been creating new users and assigning them to certain groups. I was wondering if there is a command that shows all the users assigned to a certain group? I have tried using the ‘groups’ command however whenever I use this it says ‘groups: not found’

That is the groups command. It is unlikely that you do not have it on Linux, since it is part of coreutils.

11 Answers 11

I prefer to use the getent command .

Since getent uses the same name service as the system, getent will show all information, including that gained from network information sources such as LDAP.

So for a group, you should use the following .

getent group name_of_group 

where name_of_group is replaced with the group you want to look up. Note that this only returns supplementary group memberships, it doesn’t include the users who have this group as their primary group.

There are a whole lot of other lookups that you can do . passwd being another useful one, which you’ll need to list primary groups.

The other answers doesn’t apply if you are not administrator and the group info is stored in other server.

This could be really confusing probably because of primary/secondary difference. I think this should be avoided in favor of sudo lid -g .I have a system where this answer lists 8 users in a group whereas sudo lid -g lists 10.

grep '^group_name_here:' /etc/group 

This only lists supplementary group memberships, not the user who have this group as their primary group. And it only finds local groups, not groups from a network service such as LDAP.

This could be really confusing probably because of primary/secondary difference. I think this should be avoided in favor of sudo lid -g .I have a system where this answer lists 8 users in a group whereas sudo lid -g lists 10.

This should NOT be the accepted answer. Modern Linux installations have multiple sources for user/group information — not just local /etc/passwd and /etc/group — e.g. nsswitch or sssd . Use getent passwd for user info & getent group for group information — this will cover all modern Linux configurations.

Easier to do groups [username]

If you want to list all local users and their local groups you can do

cat /etc/passwd | awk -F’:’ ‘< print $1>‘ | xargs -n1 groups

If you get «groups: command not found», it is likely you’ve edited your environmental path for the worse, to reset your path do PATH=$(getconf PATH)

It works for a particular group if | grep is added and gives the correct answer unlike getent group name_of_group or grep ‘^group_name_here:’ /etc/group

Instead of cat /etc/passwd , you should use gentent passwd so users in nis/ldap would still be listed. The only drawback is that it can take quite a while.

groupmems -g groupname -l

lists all users in the named group.

Note that groupmems is part of the shadow utils used on most Linux distros, however groupmems is currently absent from Debian and derivative (a bug now fixed but not included in any release yet (as of Nov 2016))

Also note that groupmems only deals with groups in /etc/group (not the ones in LDAP or other user database) and requires superuser privileges as it tries to open /etc/gshadow.

Despite the caveats mentioned above, this command is ideal for certain situations because it doesn’t require additional parsing of the output (i.e. cut and friends).

This could be really confusing probably because of primary/secondary difference. I think this should be avoided in favor of sudo lid -g . I have a system where this answer lists 8 users in a group whereas sudo lid -g lists 10.

groups command prints group memberships for a user. You can use lid command to list users in a group like:

Update: On Debian based distributions the command name differs as libuser-lid . Both commands are provided by libuser package as @chris-down mentioned.

$ sudo libuser-lid -g lpadmin kadir(uid=xxxx) 

What’s more, on Ubuntu 20.04 LTS, lid is part of the id-utils package. After installation it turned out that this lid does not support the -g option. I understand that Kadir answered 6 years ago, but maybe it’s time to update the information given here.

@LaryxDecidua id-utils manipulates id databases, it doesn’t work with files such as /etc/group or /etc/passwd . Its lid is not at all similar to libuser ’s.

I am surprised nobody mentioned

This command will give a list of groups the user is in.

Because — contrary to the title — the questioner wanted to know the users within a given group, not the groups of a given user, as detailed in the question. I now rephrased the title to match the contents.

Even though , is it different from the actual question, everyone will find this too as a useful information , I bet !

cut -d: -f1,4 /etc/passwd | grep $(getent group | cut -d: -f3) | cut -d: -f1 

I disagree. Because it reads users in /etc/passwd, this will not work with other nsswitch modules that access LDAP etc.

Didn’t work correctly for me: I got 4 members in a group whereas sudo lid -g lists 8. @Bhavik The accepted answer is not correct either.

Works nicely, especially if cut -d: -f1,4 /etc/passwd is replaced with getent passwd | cut -d: -f1,4 . As many people have pointed it out, getent will query non-local information sources.

Some will tell you to install libuser (for ‘lid’) or members (for ‘members’). But building upon the answer https://unix.stackexchange.com/a/349648/77959 which handled this issue with login group membership I found another group not being covered by that script. So — here’s the best of both approaches combined:

#!/bin/bash if [ $# -eq 1 ]; then gid=`getent group "$1"|cut -d: -f3` list_a=`cut -d: -f1,4 /etc/passwd | grep ":$gid$" | cut -d: -f1` list_b=`getent group "$1"|cut -d: -f4|sed 's/,/\n/g'` echo -e "$list_a\n$list_b"|grep -v "^$"|sort|uniq else echo "pass me a group to find the members of" fi 

It worked correctly on my system unlike answers involving getent or grep ‘^group_name_here:’ /etc/group

OP phrased the question to exclude the possibility of using the groups command. Since that is part of coreutils on Linux, either (a) it was removed, or (b) OP is mistyping the name.

OP could have used groups like this, for instance:

for name in $(cut -d: -f1 /etc/passwd);do groups $name|grep -w sudo|awk '';done 

One suggested answer just grep’s for the group name in /etc/group . Sometimes that works as intended.

A slightly better use of grep takes into account the syntax of /etc/group :

group_name:password:GID:user_list 

so that only the part before the first colon is a valid group-name. A plain grep without regard to syntax can (and will) pick up misleading matches from the file. Use regular expressions to make the grep match exactly what is needed:

grep -E '^users:' /etc/group |sed -e 's/^.*://' 

or using a shell variable:

grep -E '^'$groupname':' /etc/group |sed -e 's/^.*://' 

However, that only lists those not in a default group. To add those, you need to take into account the password file, e.g., by extracting the group-id number from /etc/group , and printing the users whose default group matches from /etc/passwd , e.g.,

You could do the same thing using just grep and sed, but it is more work than using awk.

Another suggested answer proposed using getent , which also is likely to be on a Linux machine (with Debian, it is part of GNU libc). However a quick check of that shows it providing only the /etc/group content.

I (like most) do not have libusers or lid installed, so I cannot comment on whether it satisfies OP’s conditions.

There is also the id program, which gives group information. Someone might expand on that as a possible answer.

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How to List Groups in Linux

In Linux, a group is a collection of users. The main purpose of the groups is to define a set of privileges like read, write, or execute permission for a given resource that can be shared among the users within the group. Users can be added to an existing group to utilize the privileges it grants.

This tutorial explains how to show all groups a user is a member of. We will also explain how to list all members of a group.

Linux Groups #

There are two types of groups that a user can belong to:

• Primary or login group – is the group that is assigned to the files that are created by the user. Usually, the name of the primary group is the same as the name of the user. Each user must belong to exactly one primary group.
• Secondary or supplementary group — used to grant certain privileges to a set of users. A user can be a member of zero or more secondary groups.

List all Groups a User is a Member of #

There are multiple ways to find out the groups a user belongs to.

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.

One way to find the user’s groups is to list the contents of those files using cat , less or grep . Another easier option is to use a command whose purpose is to provide information about the system’s users and groups.

Using the groups command #

The most memorable command to list all groups a user is a member of is the groups command. When executed without an argument the command will print a list of all groups the currently logged in user belongs to:

The first group is the primary group.

john adm cdrom sudo dip plugdev lpadmin sambashare

To get a list of all groups a specific user belongs to, provide the username to the groups command as an argument:

Same as before the first group is the primary group.

Using the id command #

The id command prints information about the specified user and its groups. If the username is omitted it shows information for the current user.

For example to get information about the user linuxize you would type:

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

uid=1001(linuxize) gid=1001(linuxize) groups=1001(linuxize),27(sudo) 

To print only the names instead of the numbers use the -n option. Option -g will print only the primary group and -G all groups.

The following command will print the names of the groups the current user is a member of:

john adm cdrom sudo dip plugdev lpadmin sambashare 

List All Members of a Group #

To list all members of a group, use the getent group command followed by the group name.

For example, to find out the members of a group with the name developers you would use the following command:

If the group exists the command will print the group and all its members:

If there is no output that means the group doesn’t exist.

List All Groups #

To view all groups present on the system simply open the /etc/group file. Each line in this file represents information for one group.

Another option is to use the getent command which displays entries from databases configured in /etc/nsswitch.conf file including the group database which we can use to query a list of all groups.

To get a list of all groups, type the following command:

The output is the same as when displaying the content of the /etc/group file. If you are using LDAP for user authentication the getent will display all groups from both /etc/group file and LDAP database.

You can also use awk or cut to print only the first field containing the name of the group:

Conclusion #

In this tutorial, you learned how to find the groups a user is a member of. The same commands apply for any Linux distribution, including Ubuntu, CentOS, RHEL, Debian and Linux Mint.

Feel free to leave a comment if you have any questions.

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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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