How to Create Multiple User Accounts in Linux?

Adding a single new user to a Linux system can be achieved through the useradd command. However, system administrators often need to add many users at once. Linux provides the newusers command for bulk user creation from a file.

Syntax

sudo newusers user_details.txt

Where user_details.txt is the file containing the details of all the usernames to be added.

User Details File Format

The user details file follows a specific format with colon-separated fields ?

UserName:Password:UID:GID:comments:HomeDirectory:UserShell

Creating the User Details File

Let's create a file with multiple user entries ?

$ cat MoreUsers.txt
uname1:pwd#@1:2112:3421:storefront:/home/uname1:/bin/bash
uname3:pwd#!@3:2112:3525:backend:/home/uname3:/bin/bash
uname4:pwd#$$9:9002:4721:HR:/home/uname4:/bin/bash

Setting File Permissions

Before using the user details file, we should set proper permissions for security ?

sudo chmod 0600 MoreUsers.txt

This ensures only the root user can read the file containing passwords.

Checking Existing Users

Let's verify the current users in the system by checking the /etc/passwd file ?

tail -5 /etc/passwd

pulse:x:117:124:PulseAudio daemon,,,:/var/run/pulse:/bin/false
rtkit:x:118:126:RealtimeKit,,,:/proc:/bin/false
saned:x:119:127::/var/lib/saned:/bin/false
usbmux:x:120:46:usbmux daemon,,,:/var/lib/usbmux:/bin/false
ubuntu:x:1000:1000:ubuntu16LTS,,,:/home/ubuntu:/bin/bash

Running the newusers Command

Now we run the newusers command to add the users from our file ?

sudo newusers MoreUsers.txt

Verifying Added Users

Let's verify that the users were successfully added ?

tail -10 /etc/passwd

pulse:x:117:124:PulseAudio daemon,,,:/var/run/pulse:/bin/false
rtkit:x:118:126:RealtimeKit,,,:/proc:/bin/false
saned:x:119:127::/var/lib/saned:/bin/false
usbmux:x:120:46:usbmux daemon,,,:/var/lib/usbmux:/bin/false
ubuntu:x:1000:1000:ubuntu16LTS,,,:/home/ubuntu:/bin/bash
uname1:x:2112:3421:storefront:/home/uname1:/bin/bash
uname3:x:2112:3525:backend:/home/uname3:/bin/bash
uname4:x:9002:4721:HR:/home/uname4:/bin/bash

Key Points

• The newusers command creates users, groups, and home directories automatically
• Passwords in the file should be encrypted or will be stored as plaintext initially
• Always set restrictive permissions (0600) on files containing user credentials
• Verify UID and GID values don't conflict with existing users

Conclusion

The newusers command provides an efficient way to create multiple user accounts from a structured text file. Always ensure proper file permissions and verify the results after bulk user creation.