List all users and groups in linux

Show all users and their groups/vice versa

I know I have existing groups and users but I’m not sure about their association. Is there an shell command I can use to list all users or all groups and a command to list all groups/users for a specified user/group? So something like showusers would list all users, and showgroups -u thisuser would show all the groups that have thisuser in it.

8 Answers 8

All groups with a specific user:

$ getent group | grep username 

I found that there is a user named speech-dispatcher that belongs to group audio (based on groups speech-dispatcher ). But it is not listed under getent group command! What is the problem?

+1 since this will also list users/groups not found in the conventional /etc/passwd & /etc/group files i.e. when a system is configured to use central directories such NIS and LDAP, or any other alternative user/group database, as long as that supports user/group enumeration.

List users and their groups:

for user in $(awk -F: '' /etc/passwd); do groups $user; done 

List groups and their users:

cat /etc/group | awk -F: '' | while read group gid members; do members=$members,$(awk -F: "\$4 == $gid " /etc/passwd); echo "$group: $members" | sed 's/,,*/ /g'; done 

While that would probably work, it seems a bit overly complicated, doesn’t it, when there are perfectly good simple one-shot commands to do this?

It certainly wouldn’t get anything that lives in a centralized repository. And that’s definitely information that you’d want to see.

If you dont care about remote users such as LDAP or NIS, to list users and their associated groups in a simple way:

cut -d: -f1 /etc/passwd | xargs groups 

root : root myuser : root www-data fuse anotheruser : anotheruser cdrom floppy audio dip video plugdev scanner bluetooth netdev 

This has the same problem as Chang’s answer in that it ignores users/groups originating in databases such as LDAP, NIS, etc.

This very neatly outputs the information in an incredibly clear format though, so can still be a useful first step. It helped jog my memory regarding the syntax of /etc/group and /etc/passwd!

List all users

While cat /etc/passwd shows all users (and a bunch of other stuff), cut -d ‘:’ -f 1 is a simple way to split each line with ‘:’ as a delimiter and extract just the first field (users). Pretty much the same as awk version.

List all groups

Guess what, very simmilar to listing users. Just parse /etc/group instead.

Another interesting way, maybe closer to what OP wanted, is compgen. Not sure about compatibility issues though.

Hi Elliot Baily, welcome to Server Fault! Please note that this question is over 5 years old, and already has a correct and accepted answer. Also note that your solution only works if users are stored in /etc/passwd; the accepted answer also works for other user databases (such as NIS or LDAP). If you want to answer old questions (which is perfectly fine!) you might want to have a look at the list of unanswered questions — plenty of questions looking for some love!

for user in $(getent passwd |awk -F: ''); do groups $user; done 

cat /etc/passwd # show all users cat /etc/group # show all groups cat /etc/passwd | grep group # show all users with specified group 

In contrast with the already accepted this does not list users/groups that originate from a remote user database such as LDAP, NIS etc.

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How to List Users and Groups in Linux, With Examples

Linux supports multiple users and groups, allowing access to be granted to only the resources required. Here’s how to list users, groups, and group membership.

Separating users and groups ensures that different people can’t accidentally interfere with each other’s files and ensures system security by denying access to vital system files.

This article details the various ways to query the users and groups on a computer running a Linux Operating System.

Listing All Users

The /etc/passwd file is a text-file database containing information on all of the users on a Linux system.

It can be viewed using the less command, which outputs a text file’s contents in a paginated manner (The list of users can be quite long).

You can also use the getent command to query the users database for your system:

getent is a tool specifically for querying various text-file databases used in the configuration of a Linux system.

The output of the above will look something like this:

pulse:x:123:128:PulseAudio daemon. /var/run/pulse:/usr/sbin/nologin gnome-initial-setup:x:124:65534::/run/gnome-initial-setup/:/bin/false gdm:x:125:130:Gnome Display Manager:/var/lib/gdm3:/bin/false linuxscrew:x:1000:1000:LinuxScrew. /home/linuxscrew:/bin/bash

You will see your user, along with a list of other users on the system – many applications and services will have their own user so that they can be granted permissions only to the system resources they require to operate, maintaining system functionality and security.

Each line in the /etc/passwd file holds the details of a single user. There are several fields, each separated by a : (colon). The values are as follows:

Value/Position	Meaning
1	The username for the user.
2	The password for the user. Usually, blank (noted by an x) as passwords are usually stored in an encrypted format in the /etc/shadow file.
3	UID (User ID) – the unique numerical identifier for the user.
4	GID (Primary Group ID) – the ID for the Primary group for the user (see below for more details). Group information is stored in the /etc/group file.
5	User Info. This field stores extra information about the user, like their full name or contact details, in a comma-separated format.
6	The users home directory – the path to the directory the user is placed in after login. For normal users, the user should have full permissions for this directory – it’s where they will store their files.
7	The path to the command line shell the user will use to operate the system. Usually, this is the path to the Bash shell, but there are other shells too. Some users do not require shell access and may have it set to /bin/false or /usr/sbin/nologin.

Listing Normal Users Only

To view only normal users – that is, users that you have created to log in and operate the computer (as opposed to users created for an application or service), run the following:

eval getent passwd <$(awk '/^UID_MIN/ ' https://cd.linuxscrew.com/etc/login.defs)..$(awk '/^UID_MAX/ ' https://cd.linuxscrew.com/etc/login.defs)>

A lot is going on here. Here’s a breakdown:

• eval is a command which will concatenate parameters following it into a single command and execute it
• gentent passwd queries the /etc/passwd file
• awk is a tool for searching for values in text
  • Here it’s first used to search the /etc/login.defs file to find out the range of numerical IDs which are assigned to normal users 0 defined by the UID_MIN and UID_MAX values in that file
  • It is then used to search the output from getent passwd for only users who have an ID in the above range.

  As this lists only normal users, the output is limited to the below on my machine:

  linuxscrew:x:1000:1000:LinuxScrew. /home/linuxscrew:/bin/bash

  Listing All Groups (And Their Members)

  The /etc/group file is (also) a text-file database containing information on all of the groups on a Linux system.

  Like the /etc/passwd file, it can be viewed using the less command, which outputs a text file’s contents in a paginated manner (the list of groups can be quite long).

  You can also use the getent command to query the groups database for your system:

  The output to both of the above will look something like this:

  colord:x:126: geoclue:x:127: pulse:x:128: pulse-access:x:129: gdm:x:130: lxd:x:131:linuxscrew linuxscrew:x:1000:

  As you can see, there are a lot of groups. Many applications and services will have their own unique group so that that service can be granted permission only to access the resources it needs – maintaining system stability and security.

  Each line in the /etc/group file represents a single group, with several information fields separated by a : (colon). The values are as follows:

  Value/Position	Meaning
  1	The name of the group
  2	Password for group. Generally not used (noted by a value of x). Can be set to enable privileged groups.
  3	GID (Group ID) – the unique numerical identifier of the group. If the group is the primary group for a user, the GID for the group will appear in the /etc/passwd file.
  4	The list of usernames for the users who are members of the group (unless it’s the users primary group – see below). Usernames are comma-separated.

  Primary and Secondary Groups

  Each user will have a single primary group and can also be a member of multiple secondary groups.

  Usually, the primary group shares its name with the user and is the default group given permissions to a file created by the user.

  The users primary group may not appear in the /etc/group file! It is usually defined in the /etc/passwd file in the GID (Group ID) field.

  Listing Groups of a Specific User

  To find out what groups you, the current user, are a member of, use the groups command

  The groups you are a member of will be listed, separated by spaces.

  To find out what groups another user is a member of, run:

  …where USERNAME is the name of the user you wish to list the groups for. You may need to run this as root or using the sudo command depending on your user permissions.

  The ‘id’ Command

  There is also the id command – it prints out the information for a user. To find information on the current user, run it:

  Or, to find information on another user, run:

  The UID (User ID), GID (Primary Group ID), and a list of all of the groups the user is a member of in the format GID(group name) will be output. It will look something like this:

  uid=1000(linuxscrew) gid=1000(linuxscrew) groups=1000(linuxscrew),27(sudo)

  Check out our other Linux Tips and Bash/Shell tutorials!

  Источник

  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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  Источник

  How To List All Users and Groups in Linux

  

  Users and group files are important for Linux. Normal users will interact with Linux systems by using credentials provided in the user ad group file.

  Print User File Named passwd

  We can get content of the user file like below. This file provides usernames home directories and shell information.

  

  As we can see each line of the output provides the user name, user id, user group, user shell, user home path etc.

  Print Only Usernames

  We can print only usernames by filtering other columns like below.

  $cat /etc/passwd | cut -d : -f 1

  

  Print Users Who Have Login

  By default normal users will login to the Linux box. But in some cases service users do not need to login Linux system. This is also a security measure. We can list users who do not have login right with the following command. This login information is stored in the /etc/passwd file.

  $ cat /etc/passwd | grep -v nologin

  

  Print Users Who Have Home Directories

  We can print only users who have home directories in /home. This command will first look in to the passwd to list users how have /home and then print only user names from result.

  $ cat /etc/passwd | grep "/home/" | awk -F':' '< print $1>'

  

  Print Group File

  Linux users have primary and secondary groups. These group names are stored in the /etc/group file. We can print this group information and assigned user with cat command. For more details read following tutorial.

  

  Print Only Group Names

  We can print only group names by cutting other column like below.

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