Linux list all users account using the /etc/passwd file
In order to list all users on Linux, use the cat command as follows: $ cat /etc/passwd Here is what I see:
Each line in the file has seven fields as follows. For example, consider the following line: vnstat:x:131:137:vnstat daemon. /var/lib/vnstat:/usr/sbin/nologin Where,
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vnstat – The user name or login name.
x – Encrypted password is stored in the /etc/shadow file.
131 – UID (user ID number)
137 – Primary GID (group ID number)
vnstat daemon – GECOS. It may includes user’s full name (or application name, if the account is for a program), building and room number or contact person, office telephone number, home telephone number and any other contact information.
/var/lib/vnstat – Home directory for the user.
/usr/sbin/nologin – Login shell for the user. Pathnames of valid login shells comes from the /etc/shells file.
How to list users in Linux using pagers
Of course we can use pagers such as more/less commands as follows to view the /etc/passwd file: $ more /etc/passwd $ less /etc/passwd Sample outputs:
Fig.01: List users using /etc/passwd
Linux list user names only
To list only usernames type the following awk command: $ awk -F’:’ ‘< print $1>‘ /etc/passwd Sample outputs:
Another option is to use the cut command: $ cut -d: -f1 /etc/passwd
Get a list of all users using the getent command
To get a list of all Linux users you can type the following getent command: $ getent passwd $ getent passwd | grep tom ## get a list all users ## $ getent passwd | cut -d: -f1 ## count all user accounts using the wc ## $ getent passwd | wc -l One can use the compgen command on Linux to list users and other resources too: $ compgen -u
Find out whether a user account exists in the Linux server
We can use above commands to see whether a user exists in the Linux machine as follows using the grep command:
A simplified command would be:
How to count user accounts in the Linux server
Want to get user accounts count on your system? Try the wc command as follows: $ compgen -u | wc -l $ getent passwd | wc -l
A Note About System and General Users
Each user has numerical user ID called UID. It is defined in /etc/passwd file. The UID for each user is automatically selected using /etc/login.defs file when you use useradd command. To see current value, enter: $ grep «^UID_MIN» /etc/login.defs $ grep UID_MIN /etc/login.defs Sample outputs:
1000 is minimum values for automatic uid selection in useradd command. In other words all normal system users must have UID >= 1000 and only those users are allowed to login into system if shell is bash/csh/tcsh/ksh etc as defined /etc/shells file. Type the following command to list all login users:
To see maximum values for automatic uid selection in the useradd command, enter: $ grep «^UID_MAX» /etc/login.defs Sample outputs:
In other words, all normal system users must have UID >= 1000 (MIN) and UID /etc/shells file. Here is an updated code to get details:
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How to List Users in Linux, List all Users Command
Home » SysAdmin » How to List Users in Linux, List all Users Command
Linux OS is unique because of its multi-user characteristic allowing multiple users on one system, at the same time. However, tracking all users is essential.
In this article, earn multiple commands to list all Linux users along with their login information. These commands work on CentOS, Ubuntu, Arch Linux, and other Linux distributions as well.
A Linux distribution installed and running
A user with sudo privileges
Access to a terminal/command line
List All Linux Users, 2 Options
List All Users in Linux with the /etc/passwd File
Details of local users can be found in the /etc/passwd file. Every line contained in the file contains the information of one user.
There are two options.
Open the etc/passwd file by typing the command:
Alternatively, you can use the less command:
Note: To display a list of the logged-on users and the information such as boot time, processes, hostnames, and more, use the who command.
List All Linux Users with the getent Command
Database entries configured in the /etc/nsswitch.conf file include the passwd database with all the usernames and login information.
To extract this data, use the command:
Both Option 1 and Option 2 will display all the users and their login information.
Each line represents one user and has seven (7) fields.
The fields are separated by : (colons) and each line includes the following information:
1. Username 2. The encrypted password (represented by x, located in the /etc/shadow file) 3. User ID number (known as UID) 4. User group ID (known as GID) 5. User full name 6. User home directory 7. The login shell (by default set to bin/bash)
How to Only List Linux Usernames
In case you don’t need all the information related to each user, you can list only the usernames on the system. There are two ways to see just the first field (the username) of each user.
Option 1: Using the awk or cut command.
To list usernames only, you can use either of the following two (2) commands:
Option 2: Using the getent command with awk and cut .
To read and display the username without any additional information using the getent command, run the following command:
Alternatively, use the command:
How to Search for Existing Linux Users
The getent command also allows you to check whether a user is present on the system.
Any of the following two commands will provide you with that information:
If the user exists, it will display login information. On the other hand, if there is no such user, there will be no output.
For example, in the image below, the query displays whether a user named example exists. The output proves that such a user exists.
System User vs Normal User
A system user is the one that creates normal users. Therefore, in this instance, the system user is the root. This user is created when you first install the Linux operating system. Additionally, you can create system users for particular applications.
On the other hand, normal users are all users that the root (or a user with sudo privileges) creates. Each normal and system user has a real login shell, home directory, as well as a user ID (UID) number. The user ID number is given automatically in the range between the minimum and maximum values.
How to Check UID_MIN and UID_MAX
If you want to check what the UID range for normal users is, use grep with the following command:
The output shows that all normal users have a UID anywhere from 1000 (UID_MIN) to 6000 (UID_MAX).
Note: Change the values in the command according to the minimum and maximum UID values for your system.
How to List Normal Users
With these numbers in mind, you ask for a list of all the users in that range with the command:
The query lists all the normal users, as seen in the image below. In this example, there are two normal users in the specified range.
After reading this guide, you should know how to list all Linux users, search for users, and find the number of Linux users in any Linux distribution ( Ubuntu, CentOS, RHEL, Debian, and Mint).
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How to List All Users in a Linux System
At times, a change in user privileges might be necessary. For example, a user might need his or her privileges extended for a certain task, or a ability of a certain user to access the system may have to be revoked entirely. In such scenarios, it is important for the system administrator to have complete knowledge of all users of the system.
In this article, we explore the methods used to list the users of a Linux system. Both graphical user interface (GUI)-based methods and command line interface (CLI)-based methods can be used for this task; however, this article focuses on four terminal-based methods.
Note: While the methods discussed below are carried out on a Linux Mint 20 system, you can use the Linux distribution of your choosing.
Method # 1: The “cat” command
To use the “cat” command to list all users in a Linux system, the following steps should be performed in order:
Launch the terminal.
Use the “cat” command to list all the users on the terminal to display all the user account details and passwords stored in the /etc/passwd file of the Linux system.
As shown below, running this command will display the usernames, as well as some additional information. You can scroll through this list to view all the users of the Linux system.
Method # 2: The “awk” command
The “awk” command is helpful if you want to display usernames only, which may be useful if you do not need all the technical details returned with the “cat” command. To use this command to list all users in a Linux system, the following steps should be performed in order:
Launch the terminal.
Run the following command:
When you run this command in your terminal, only the usernames will be returned. This list includes all the users of the Linux system.
Method # 3: The “compgen” command
Like the “awk” command, this command is used to display only usernames, ignoring all other details. To use the “compgen” command to list all users of the Linux system, the following steps should be performed in order:
Launch the terminal.
Run the following command:
This command will return all the usernames associated with your Linux operating system.
Method # 4: The “getent” command
The output of the “getent” command is very similar to that of the “cat” command, as it displays a lot of details along with the usernames. To use the “getent” command to list all users in the Linux system, the following steps should be performed in order:
Launch the terminal.
Run the following command:
This command will list all the users of your Linux system, as well as some other details, as shown in the image below.
Conclusion
Depending on your requirements, you can choose from the four commands discussed in this article to obtain a list of users. Two of these methods, in addition to listing all the users of your Linux system, also provide some important details for all of user accounts.
There are variations of these commands that you can experiment with to suit your needs. However, such variations are beyond the scope of this article. The methods we discussed herein will allow you to list all the users of your Linux system. I hope this article helped you to better understanding this topic.
About the author
Aqsa Yasin
I am a self-motivated information technology professional with a passion for writing. I am a technical writer and love to write for all Linux flavors and Windows.
