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 on Ubuntu Linux VPS
In this article, we will show you how to list users on Ubuntu VPS. By the end of this tutorial, you’ll be able to perform some basic commands to view all registered users and groups to manage your system administration. So, without further ado, let’s get started.
Reasons to View System Users in Ubuntu
Linux is popular among tech research groups and development communities because it is suitable for team-based projects. This means that oftentimes, a Linux-based system is used by multiple users at the same time.
For that reason, managing these users and groups is a day-to-day task. System administrators can take advantage of Ubuntu’s complete features to control how users and groups interact with the system.
For instance, you can grant certain users and groups to access specific files and folders. What’s more, you can adjust configuration and administrative rights to modify your system and secure your data by preventing any harmful anonymous process.
However, before configuring those settings, it is better to learn how to list users on Ubuntu VPS or server. The reason is simple: you will need to see their permissions and activities to verify every operation on your machine.
Do note that since we will list users on Ubuntu VPS, we have to use the command line to access it. You can work with the terminal shell (Linux and macOS) or PuTTY (Windows). If you’re a Hostinger user, the login credentials are located in the hPanel’s Servers tab.
How to List Users on Ubuntu
We are going to divide this tutorial into three parts — viewing all users, viewing groups, and viewing logged in users.
Viewing All Users on Linux
Linux stores all the information about user registrations in a file called passwd, which is located at /etc/passwd.
To access the content of the file, open your terminal and type the following command:
The script will return a list that looks like this:
In the output above, each line corresponds to a user. The number of lines will depend on the number of registered users.
Each line contains seven fields that are separated by colons (:). These fields hold specific information about a particular user.
Let’s take a look at the first line:
Here are the meanings of each field, from left to right:
root — the login name of the user.
b — placeholder for the password (the actual password is stored in a separate file).
0 — User ID, which is unique for each registered user. By default, root has the User ID of 0.
0 — Group ID. Like User ID, it is unique for every user.
root — Comment field. Contains a short description of the user, usually filled out with users’ full name.
/root — Home directory. This is the main directory of the users. For users other than root, the folder will be /home/username.
/bin/bash — User shell. Refers to the shell that users use to sign in to the system.
If you only want to view the name of the users, you can run this special command:
Viewing Groups on Linux
In Linux, you also have the option to create groups. You basically gather several users and grant them joint privileges or access. It is particularly useful if multiple teams are using the same system.
Unlike users, the group information is stored in a file named group that can be found at /etc/group.
To view the contents of this file, simply open up the terminal and type the following command:
The line above should give this output:
Notice that the group names are exactly the same as the name of our users. This is the result of user private groups (UPG), a scheme employed by Linux where each user will have their own private group.
Just like the previous one, it is possible to view the group names only:
Viewing Logged In Users
To list logged in users, simply type the following letter in your terminal:
Besides showing the active users, the command also provides some additional information like login time, remote host, and idle time. The full results will look like this:
Let’s breakdown the results of the w command:
User — username.
TTY — terminal name
From — the name of the remote host.
Login@ — login time.
Idle — idle time.
JCPU — the amount of time used by processes attached to the TTY.
PCPU — the time used by the process displayed in the WHAT field.
WHAT — the user’s current process.
Alternatively, there is another command that performs a similar function to w:
However, the results won’t be as detailed as the w command:
Conclusion
Linux is a perfect OS for team-based projects because many people can log in to the same system. Due to this nature, it is important to learn how to manage users for better system administration.
The first lesson you need to know is to list the registered users, which will be useful to verify all operations and protect your data.
In this guide, we have shown you how to list users on Ubuntu VPS using simple commands. In addition, you’ve also learned how to view all groups and monitor every logged-in user.
Good luck and be sure to check other VPS tutorials!
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UNIX / Linux List Current Logged In Users
H ow do I print the user names of users currently logged in to the current UNIX / Linux host / server from a command prompt?
You need to use any one of the following command line tools to list currently logged in users on Linux or Unix-like systems.
Tutorial details
Difficulty level
Easy
Root privileges
Yes
Requirements
w or who command on Linux and Unix
Est. reading time
5m
The following two file keep login records on Linux and Unix-like systems:
/var/run/utmp – Keeps and allows us to discover information about who is currently using the system. Please note that there may be more L inux and Unix users currently using the system, because not all programs use utmp logging . In other words, poorly written app, hidden programs, malware, and other bad stuff will not be useful to list logged in users.
/var/log/wtmp – Keeps records all logins and logouts.
We simply cannot read these files using cat command/grep command/egrep command as file is in binary database format. Hence, we use the following commands to find currently logged in users in Linux and Unix-like systems.
Linux Command To List Current Logged In Users
w command – Shows information about the users currently on the machine, and their processes.
who command – Display information about users who are currently logged in.
users command – See the login names of the users currently on the system, in sorted order, space separated, on a single line. It reads all information from /var/run/utmp file.
How to find currently logged in users in Linux
Open a terminal (or login into remote server using ssh command) and type the following commands.
Using w command to list current logged in users under Unix or Linux
Open the terminal application and then type the w command: $ w
Fig.01: w command in action.
Understanding w command outputs
From Fig.01 we see the following for each user:
USER – Linux or Unix login name.
TTY – The tty name.
FROM The remote host or IP address.
@Login – Login time.
IDEL – Idle time.
JCPU – The JCPU time is the time used by all processes attached to the tty. However, it does not include past background jobs, but does include currently running background jobs.
PCPU – The PCPU time is the time used by the current process, named in the “what” field.
WHAT – The command line of that users current process.
To see info about a user named tom, enter: $ w tom Tell w command not print header: $ w -h $ w —no-header We can also ignore current process username by passing the -u or —no-current to the w command: $ w -u $ w —no-current Want to see remote hostname field? Try: $ w -f Show IP address instead of hostname for from field: $ w -i We can also old style output. In other words old outputs prints blank space for idle times less than one minute: $ w -o
Display all logged in users using who command
The who command works on all Unix like operating systems such as macOS, *BSD, Linux and so on. The syntax is pretty simple: # who Here is what we see:
The who command displays the following information:
root – The username
pts/0 – Type of the terminal device. In this example, we see pseudoterminal pts/0 used by root user.
2013-03-12 15:10 – User login date and time stamp.
(10.1.3.177) – The remote IP address from which the user logged into this server.
We can pass the -a option to who command as follows to see time of last system boot, display dead processes, system login processes, active processes spawned by init/systemd, print current runlevel, print last system clock change, show user’s message status, and list users logged in to Linux or Unix box: # who -a Here is output from older Linux system (pre Systemd):
Sample outputs from Systemd based Linux sysetem:
Getting help with the whois command
You can pass the following options to the who command (taken from the who command man page):
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users command
Open a terminal or login over the ssh session and enter the following users command: $ users Output who is currently logged:
Vieing logged in users with last command
Want to see a listing of last logged in users? Use the last command to lookup binary database called /var/log/wtmp and displays a list of all users logged in (and out) since that file was created. For instance see history for user named ‘vivek’: $ last vivek
