How to list all users in Linux (Ubuntu)

ubuntu

A Linux system can have many users that can log in to the server. The user accounts are stored in the /etc/passwd file. You can view this file to see what users are able to log in. The easiest way to retrieve the list of users is by viewing the contents of /etc/passwd text file.

Table of Contents

  1. View the contents of /etc/passwd file
  2. Use the ‘awk’ command to display all user accounts in ubuntu
  3. Create a New User
  4. Get info about a specific user
  5. Conclusions

View the contents of /etc/passwd file

If you wish to view the contents of /etc/passwd just type cat into Terminal. The cat command outputs the full-text contents of the file.

cat /etc/passwd

Each row in the result set corresponds to a user. You can see some useful information about each user. The seven columns are:

  1. Username
  2. Encrypted Password
  3. User ID (UID)
  4. Group ID (GUID)
  5. User ID Info (GECOS)
  6. Home Directory Path
  7. Command Shell (bash, sh, nologin, etc.)

The first item of each line before the “:” separator is the username.

Use the ‘awk’ command to display all user accounts in ubuntu

Using the ‘awk’ command, we can extract only the first field from the /etc/passwd file. Awk is a powerful text manipulation tool in Linux.

awk -F: '{print $1}' /etc/passwd

This command lists each user’s full name on the system.

Example output of running the awk command above on an Ubuntu server.

$  awk -F: '{print $1}' /etc/passwd
root
daemon
bin
sys
sync
games
man
lp
mail
news
uucp
proxy
www-data
backup
[...]

Create a New User

Apart from listing all users in Ubuntu, it is important to know how to add a new user. To create a new user in Linux, use this command:

To add a new user, type 

sudo useradd newusername

This will create a new user record in the /etc/passwd file.

Get info about a specific user

Use the grep command to search through the /etc/passwd file to see whether any specific username exists. This is helpful if there are many users in the /etc/passwd file. This can help check for the existence of a particular user.

grep -i username /etc/passwd

We can obtain information about a particular user called “username” by reading their /etc/passwd file.

Conclusions

This tutorial shows us how to list all the users in a Linux system along with how to add a new user. Mainly how to access the /etc/passwd file and add a new user.