How to Add a User in Linux Using the useradd Command March 29, 2025

This article explains how to add a user in Linux using the useradd command.

The useradd command in Linux is used to create new user accounts on a system. It is a native binary compiled with the system, whereas adduser is a Perl script that utilises useradd in the background. When a new user is added, useradd makes changes to the following files:

• /etc/passwd
• /etc/shadow
• /etc/group
• /etc/gshadow
• Creates a user directory under /home (if specified)

Syntax of the useradd Command
The basic syntax of the useradd command is:

useradd [options] [username]

Let us manage users with the useradd command:

1. Adding a New User in Linux
   To create a new user, use the following command:

   sudo useradd test_user

   This command creates a new user named test_user but does not set a password or create a home directory by default.

2. Adding a User with a Specific Home Directory
   To specify a custom home directory, use the -d flag:

   sudo useradd -d /home/test_user test_user

   This sets /home/test_user as the user’s home directory.

3. Creating a User with a Specific User ID (UID)
   To assign a custom User ID (UID):

   sudo useradd -u 1234 test_user

   This creates test_user with the UID 1234.

4. Creating a User with a Specific Group ID (GID)
   To assign a Group ID (GID) while creating a user:

   sudo useradd -g 1000 test_user

   This assigns test_user to the group with GID 1000.

5. Creating a User Without a Home Directory
   To create a user without a home directory, use the -M option:

   sudo useradd -M test_user

   This prevents the creation of /home/test_user.

6. Creating a User with an Expiry Date
   To set an expiry date for a user account:

   sudo useradd -e 2025-12-31 test_user

   This sets the account expiry date to December 31, 2025.

7. Adding a Comment or Description for a User
   To include a comment describing the user:

   sudo useradd -c "This is a test user" test_user

   This assigns “This is a test user” as the user description.

8. Creating a User with a Custom Login Shell
   To set a specific shell for a user:

   sudo useradd -s /bin/sh test_user

   This assigns /bin/sh as the default shell instead of the system default.

9. Setting an Unencrypted Password for the User
   To assign a password (not recommended due to security concerns):

   sudo useradd -p test_password test_user

   This sets test_password as the user’s password in an unencrypted format. It is advisable to use passwd instead:

   sudo passwd test_user

10. Displaying Help for useradd
    To view available options and syntax:

    sudo useradd --help

    This displays all possible flags and their descriptions.

This way, we can conclude that the useradd command is a powerful tool for creating and managing user accounts in Linux.

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