How to Change Username on Ubuntu

Changing your username on Ubuntu might be necessary for various reasons—perhaps you’ve changed your legal name, inherited a computer with someone else’s account, or simply want a more professional username for your work environment. While this process isn’t as straightforward as changing a password, with the right guidance, you can safely modify your Ubuntu username without compromising your system. This comprehensive guide walks through the entire process of changing a username in Ubuntu, covering both graphical and command-line methods, along with potential pitfalls and their solutions.

Understanding Username Structure in Ubuntu

Before diving into the process of changing usernames, it’s essential to understand how Ubuntu handles user accounts and the system architecture behind them.

User accounts and system architecture

In Ubuntu, like other Linux distributions, usernames are more than just labels. They’re integral parts of the operating system’s security model. Each username corresponds to a unique User ID (UID), which the system uses to track file ownership and access permissions. Your username is tied to your home directory (typically /home/username) and is referenced in numerous configuration files throughout the system.

Ubuntu distinguishes between your login username (what you type at the login screen) and your display name or “real name” (what appears in the user interface). While changing your display name is a simple task, modifying your login username requires more care.

Implications of changing a username

Changing your username affects more than just what you type at login. It impacts:

• File and directory ownership throughout the system
• Application configurations that reference your home directory path
• System services that may be configured to run under your user account
• Scheduled tasks (cron jobs) associated with your account
• Group memberships and permissions

This interconnected nature makes username changes more complex than they might initially seem, requiring careful planning and execution.

Prerequisites Before Changing Username

Proper preparation prevents poor performance. This adage holds especially true when modifying core system elements like usernames in Ubuntu.

Creating a system backup

Before attempting to change your username, create a comprehensive backup of your system. At a minimum, back up your entire home directory and essential system configuration files. For maximum safety, consider a full system backup using tools like Timeshift, Déjà Dup, or a simple rsync command to an external drive.

sudo apt install timeshift
sudo timeshift --create --comments "Before username change"

Alternatively, for a manual backup of your home directory:

sudo rsync -aAXv /home/yourusername/ /path/to/backup/location/

Required permissions and access

Changing a username requires administrative privileges. You’ll need sudo access or root permissions to execute the necessary commands. Importantly, you cannot change the username of an account while logged into that account. The user account being modified must be logged out, which creates a logistical challenge requiring planning.

Preparing for the change

Before proceeding, create a detailed checklist:

• Identify all services running under your user account
• Note any applications with hardcoded paths to your home directory
• Document your current group memberships with: groups username
• List all files owned by your account outside your home directory:

  sudo find / -user yourusername -not -path "/home/*" -not -path "/proc/*" 2>/dev/null

• Ensure you have another administrative user account available for the process

Creating a Temporary Administrator Account

Since you can’t change your own username while logged in, you’ll need an alternative administrative account to perform the changes.

For Ubuntu Desktop users

1. Open Settings and navigate to “Users” or “User Accounts”
2. Click the “Add User” or “+” button
3. Fill in the required information for the new temporary user
4. Make sure to set the account type to “Administrator”
5. Set a secure password that you’ll remember
6. After creating the account, log out of your current session

Creating this temporary account through the GUI is straightforward and provides a safety net in case anything goes wrong during the username change process.

For Ubuntu Server/SSH users

If you’re working with Ubuntu Server or accessing your system via SSH, create a temporary admin user with these commands:

sudo adduser tempAdmin
sudo usermod -aG sudo tempAdmin

After creating the temporary user, verify that it has sudo privileges:

su - tempAdmin
sudo -l

The command should list the sudo privileges available to the temporary user. If correctly configured, you can proceed with the username change process.

The Username Change Process

Now that preparations are complete, let’s execute the username change.

Logging out and switching users

First, ensure that the user account you want to modify is completely logged out of all sessions. Check for any active processes:

sudo ps -u oldusername

If needed, terminate persistent processes:

sudo pkill -u oldusername

Then log in with your temporary administrator account.

Changing the username with usermod

The primary command for changing a username in Ubuntu is usermod. This powerful tool modifies user account properties, including the username itself. Here’s the basic syntax:

sudo usermod -l newusername oldusername

This command changes only the username, not the home directory or group name. For example, to change a username from “john” to “jonathan”:

sudo usermod -l jonathan john

Updating the group name

In Ubuntu, each user typically has a primary group with the same name as their username. After changing the username, you should update this group name to maintain consistency:

sudo groupmod -n newusername oldusername

This keeps your primary group aligned with your new username, helping prevent permission issues. For our example:

sudo groupmod -n jonathan john

Modifying the home directory

By default, changing your username doesn’t update your home directory path. You have two options:

1. Create a new home directory and move the contents:

   sudo mkdir /home/newusername
   sudo cp -r /home/oldusername/. /home/newusername/
   sudo chown -R newusername:newusername /home/newusername

2. Rename the existing home directory:

   sudo usermod -d /home/newusername -m newusername

The second option uses the -m flag to move the contents automatically. For our example:

sudo usermod -d /home/jonathan -m jonathan

Creating symbolic links for compatibility

Some applications might still reference the old home directory path. Creating a symbolic link can help during the transition:

sudo ln -s /home/newusername /home/oldusername

This link redirects access attempts to the old path toward the new location, reducing the likelihood of application errors.

Step-by-Step Username Change Guide

Let’s consolidate what we’ve learned into a sequential procedure for two common scenarios.

Method 1: For Ubuntu Desktop users

1. Create a temporary administrator account through System Settings > Users
2. Log out completely from your current account
3. Log in with the temporary administrator account
4. Open Terminal and execute these commands in sequence:

   sudo usermod -l newusername oldusername
   sudo groupmod -n newusername oldusername
   sudo usermod -d /home/newusername -m newusername
   sudo ln -s /home/newusername /home/oldusername

5. Update the display name (optional):

   sudo chfn -f "New Display Name" newusername

6. Verify the changes:

   ls -la /home/
   grep newusername /etc/passwd

7. Log out from the temporary account
8. Log in with your new username
9. Test that applications function correctly
10. Once satisfied, you can remove the symbolic link and temporary admin account

Method 2: For Ubuntu Server/SSH users

For headless servers or SSH connections, the process requires additional care:

1. Connect via SSH and create a temporary admin user:

   sudo adduser tempAdmin
   sudo usermod -aG sudo tempAdmin

2. Disconnect and reconnect using the temporary account:

   ssh tempAdmin@your-server-ip

3. Check for and terminate processes for the old username:

   sudo ps -u oldusername
   sudo pkill -u oldusername

4. Perform the username change:

   sudo usermod -l newusername oldusername
   sudo groupmod -n newusername oldusername
   sudo usermod -d /home/newusername -m newusername

5. Check for and update any service configurations:

   sudo grep -r "oldusername" /etc/

6. Test logging in with the new account in a separate session
7. After confirming everything works, remove the temporary admin account

Managing Application Settings After Username Change

After changing your username, some application settings may need adjustment.

Default application configurations

Many applications store their configurations in hidden directories within your home folder (files and directories that start with a dot, like .config). While the file ownership changes when you move your home directory, some applications may have hardcoded paths or references to your old username.

Common locations to check include:

• ~/.config/
• ~/.local/share/
• ~/.cache/
• Application-specific directories like ~/.mozilla/ for Firefox

Most modern applications adapt automatically to home directory changes, but legacy applications might struggle.

Application-specific considerations

Some applications require special attention after username changes:

1. Email clients: Check account settings and mail storage locations
2. Database servers: Update user permissions and ownership
3. Development environments: Update paths in project configurations
4. Web servers: Verify virtual host configurations and file permissions
5. SSH: Update ~/.ssh/config if it contains references to your old home path

For databases like MySQL or PostgreSQL, you might need to update user accounts:

sudo -u postgres psql -c "ALTER USER oldusername RENAME TO newusername;"

Fixing Permissions and Ownership

After changing your username, ensure file permissions and ownership are correctly updated.

Understanding file ownership issues

In Linux, every file and directory has an owner and a group assignment. When you change your username, files previously owned by your old username might need ownership updates, especially if they’re located outside your home directory.

To find files owned by your old username:

sudo find / -user oldusername -not -path "/proc/*" -not -path "/sys/*" 2>/dev/null

Commands to correct permissions

Use the chown command to update ownership of files and directories:

sudo chown -R newusername:newusername /path/to/directory

For system-wide files that should be owned by your user:

sudo find / -user oldusername -not -path "/proc/*" -not -path "/sys/*" 2>/dev/null | xargs sudo chown newusername:newusername

Automating permission fixes

For extensive file collections, you might want to create a simple script to update permissions:

#!/bin/bash
# Change ownership of files from old user to new user
old_user="oldusername"
new_user="newusername"

sudo find / -user $old_user -not -path "/proc/*" -not -path "/sys/*" 2>/dev/null | while read file; do
    echo "Changing ownership of $file"
    sudo chown $new_user:$new_user "$file"
done

Save this as fix_permissions.sh, make it executable with chmod +x fix_permissions.sh, and run it with proper precautions.

Special Considerations for System Services

Some system services might be configured to run under your user account, requiring additional attention.

Identifying affected services

To identify services that might reference your old username:

sudo grep -r "oldusername" /etc/systemd/
sudo grep -r "oldusername" /etc/

Pay special attention to:

• Systemd service files (.service)
• Cron jobs (/etc/cron.d/ or user crontabs)
• Web server configurations (/etc/apache2/, /etc/nginx/)
• SSH configurations (/etc/ssh/)

Updating service configurations

For systemd services, edit the service files:

sudo systemctl edit servicename

After updating service configurations, reload systemd and restart the affected services:

sudo systemctl daemon-reload
sudo systemctl restart servicename

For cron jobs in the user’s crontab, you may need to recreate them:

sudo crontab -u newusername -e

Post-Change Verification

After completing the username change, thorough testing ensures everything works as expected.

Testing the new username

1. Log in with your new username
2. Verify access to your files and applications
3. Check system integration:

   id
   groups
   ls -la ~

4. Test sudo access:

   sudo whoami

5. Verify application functionality, especially those with user-specific configurations

Troubleshooting common issues

If you encounter issues after logging in:

• Check file permissions in your home directory
• Verify environment variables with env | grep HOME
• Check for error messages in system logs:

  journalctl -b | grep -i error

• Review application-specific logs for errors related to file paths or permissions

Advanced Scenarios and Solutions

Some situations require additional considerations beyond the standard username change process.

Handling encrypted home directories

If your home directory is encrypted using Ubuntu’s built-in encryption (ecryptfs), changing your username becomes more complex. You’ll need to:

1. Backup all data from the encrypted home
2. Complete the username change as described earlier
3. Set up encryption for the new user
4. Restore the data to the newly encrypted home

The specific commands depend on your Ubuntu version and encryption setup. Consider whether decrypting temporarily might simplify the process.

Multi-user systems and shared resources

On systems with multiple users, changing a username requires additional considerations:

1. Check for shared groups and update as needed:

   grep newusername /etc/group

2. Update permissions for shared directories:

   sudo find /shared -group oldusername -exec chgrp newusername {} \;

3. Notify other users about the change, especially if they reference your home directory in scripts or configurations
4. Update ACLs if used:

   sudo getfacl -R /path/to/shared | sed "s/oldusername/newusername/g" | sudo setfacl --restore=-

Best Practices and Tips

Experience from system administrators provides valuable insights for username changes.

When to change username vs. create new user

Consider creating a new user instead of changing an existing username when:

• The existing user has complex configurations that would be difficult to migrate
• You want to keep the old account for reference or compatibility
• You need to maintain different permission sets
• The system has many customizations tied to the username

Creating a new user is simpler but requires manual data migration:

sudo adduser newusername
sudo usermod -aG sudo newusername
sudo rsync -av /home/oldusername/ /home/newusername/
sudo chown -R newusername:newusername /home/newusername/

Documentation and record-keeping

Throughout the username change process, maintain detailed notes:

• Commands executed and their output
• Any errors encountered and their solutions
• Files and configurations modified
• Before and after states of critical system components

This documentation proves invaluable if you need to troubleshoot issues later or replicate the process on another system.

Troubleshooting Guide

Even with careful preparation, issues may arise during or after a username change.

Common errors during username change

1. “User is currently used by process” error:

   Solution: Find and terminate all processes running as the old user

   sudo ps -u oldusername
   sudo pkill -9 -u oldusername

2. “Cannot lock /etc/passwd” error:

   Solution: Check for other processes trying to modify user information

   sudo lsof /etc/passwd

3. Home directory not moved correctly:

   Solution: Manually move and update ownership

   sudo mv /home/oldusername /home/newusername
   sudo chown -R newusername:newusername /home/newusername

4. “Authentication failure” when trying to log in:

   Solution: Verify password hasn’t been inadvertently changed

   sudo passwd newusername

Recovery options if things go wrong

If you encounter serious issues:

1. Log in with the temporary admin account
2. Restore from your backup if available
3. For unbootable systems, use Ubuntu recovery mode or a live USB
4. As a last resort, reverse the username change:

   sudo usermod -l oldusername newusername
   sudo groupmod -n oldusername newusername
   sudo usermod -d /home/oldusername -m oldusername