Understanding List Users in Linux

Before diving into the commands, it is helpful to understand how Linux categorizes users. Broadly speaking, there are:

• System Users: These are users created by the system or during package installations. They typically run background services and processes.

• Regular Users: These are user accounts created for human users to log in and interact with the system.

Both system and regular users are stored in the /etc/passwd file, along with important metadata like user ID (UID), group ID (GID), home directory and login shell.

How to List Users in Linux?

There are multiple ways to List Users in Linux all users in a Linux system. Here are the most common and reliable methods.

1. Viewing the /etc/passwd File

The primary method to list all users on a Linux system is by inspecting the /etc/passwd file.

cat /etc/passwd

Each line in this file represents a user, formatted as:

username:x:UID:GID:comment:home_directory:shell

Example output:

john:x:1001:1001:John Doe:/home/john:/bin/bash

To extract just the usernames from the /etc/passwd file:

cut -d: -f1 /etc/passwd

This will return a list of all usernames on the system including both regular and system users.

2. Using the getent Command

Another method to list users in Linux is with the getent command, which retrieves entries from administrative databases supported by the Name Service Switch (NSS). This is a more flexible approach especially in environments using Lightweight Directory Access Protocol or other authentication mechanisms.

getent passwd

Like cat /etc/passwd, this lists all users but through the NSS interface.To show only usernames:

getent passwd | cut -d: -f1

Read more: How to Fix Kali Linux Black Screen?

Filtering Regular Users

In Linux, user IDs (UIDs) help distinguish between system and regular users:

• System users typically have UIDs below 1000.

• Regular users generally have UIDs of 1000 or higher.

To list only regular users, use:

awk -F: ‘$3 >= 1000 && $3 < 65534 { print $1 }’ /etc/passwd

This command filters the /etc/passwd file and shows only users with UIDs in the typical range for human users.

Alternatively, using getent:

getent passwd | awk -F: ‘$3 >= 1000 && $3 < 65534 { print $1 }’

Read more: 40 Linux Commands Every Linux User Must Master

How to List Currently Logged-In Users?

If you are looking to find out who is currently logged into the system, rather than a list of all accounts, use one of the following commands:

1. who Command

who

This will show usernames, login terminals and login times.

2. w Command

w

The w command gives a more detailed output including the current activity of each user.

3. users Command

users

This outputs a simple list of logged-in usernames.

How to List Usernames in Linux?

To list only usernames (without extra information like UID or home directory), use:

cut -d: -f1 /etc/passwd

This is particularly useful for scripting or automation tasks where you need a clean list of usernames.

For example, to save the list to a file:

cut -d: -f1 /etc/passwd > all_users.txt

To count the total number of users:

cut -d: -f1 /etc/passwd | wc -l

How to Get User Details in Linux?

To get detailed information about a specific user, you can use the id command:

id username

Example:

id john

This might return something like:

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

You can also check the user’s home directory and shell by using:

getent passwd john

Which returns a line like:

john:x:1001:1001:John Doe:/home/john:/bin/bash

List Users with compgen

On Bash systems, you can use compgen to list users:

compgen -u

This shows all usernames known to the shell, similar to listing from /etc/passwd.

Conclusion

Whether you are using Ubuntu or another Linux distribution, knowing how to list users is a fundamental administrative skill. You can rely on /etc/passwd, the getent command and tools like cut, awk and compgen to explore and filter users. For real-time monitoring, tools like who, w and users help track logged-in accounts.

By mastering these commands, you will be well-equipped to manage user accounts securely and efficiently. Whether you are scripting automation tasks or maintaining server access, being able to list users in Linux is a key part of system administration.

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