How do I change username in Linux?

You can use the usermod command with -l option to rename a user, along with updating the home directory using -d and -m flags.

Can I rename a logged-in user in Linux?

No, you cannot rename a user who is currently logged in. You must switch to another user or root before performing the operation.

Does changing username affect home directory?

Yes, you should update the home directory path using usermod or manually rename it to match the new username.

How to rename user without usermod?

You can manually update /etc/passwd, /etc/group, and /etc/shadow files and rename the home directory accordingly.

How to Change Username in Linux (usermod & Manual Method Explained)

Changing a username in Linux is a common system administration task, whether for renaming users, maintaining naming conventions, or fixing incorrect usernames. This guide covers multiple methods including usermod, manual system file updates, and GUI-based approaches for Ubuntu.

Method 1: Change Username Using usermod (Recommended)

The usermod command is the safest and most recommended way to change a username in Linux. It updates the username along with the home directory and associated metadata.

Most Linux distributions create a group with the same name as the user by default (using :contentReference[oaicite:0]{index=0}). So when you rename a user, you should also update the group name to maintain consistency.

Before proceeding, make sure you have appropriate privileges using sudo or root access. You can verify your permissions using this guide on checking sudo access.

Rename user and update home directory:

bash

sudo usermod -l newuser -d /home/newuser -m olduser

Explanation:

-l → specifies the new username
-d → sets the new home directory path
-m → moves the existing home directory content to the new location

After renaming the user, update the group name (if it matches the old username):

bash

sudo groupmod -n newuser olduser

Verify the changes:

bash

getent passwd newuser
id newuser

What happens to file ownership?

All files owned by the user are linked internally using UID (User ID), not the username.
Since the UID remains unchanged, file ownership is automatically preserved.
You do not need to manually update ownership for most files.

However, always verify critical directories:

bash

ls -ld /home/newuser

If required, you can fix ownership manually:

bash

sudo chown -R newuser:newuser /home/newuser

For more details on managing users, refer to:

Method 2: Rename User Manually (Advanced)

This method is useful when usermod cannot be used or when you need full control over how user details are updated. It involves manually modifying system files that store user and group information.

WARNING

This approach is risky if not done carefully. Always take a backup of critical files before making changes:

bash
sudo cp /etc/passwd /etc/passwd.bak
sudo cp /etc/group /etc/group.bak
sudo cp /etc/shadow /etc/shadow.bak

Step 1: Update /etc/passwd

The /etc/passwd file stores basic user information such as username, UID, home directory, and shell.

bash

sudo vi /etc/passwd

Change:

text

olduser:x:1000:1000:olduser:/home/olduser:/bin/bash

To:

text

newuser:x:1000:1000:newuser:/home/newuser:/bin/bash

Here:

Username is updated from olduser → newuser
Home directory path is also updated

Step 2: Update /etc/group

The /etc/group file stores group information. If a group exists with the same name as the user, update it as well:

bash

sudo vi /etc/group

Change any occurrence of olduser to newuser.

Step 3: Update /etc/shadow

The /etc/shadow file stores encrypted password and account-related details.

bash

sudo vi /etc/shadow

Update the username field from olduser to newuser while keeping the password hash unchanged.

Step 4: Rename home directory

After updating system files, rename the user’s home directory:

bash

sudo mv /home/olduser /home/newuser

Fix ownership:

bash

sudo chown -R newuser:newuser /home/newuser

What happens to file ownership?

Just like with usermod, Linux tracks ownership using UID and GID, not usernames.
Since UID/GID are unchanged, most file ownership remains intact.
However, after manual changes, it is recommended to verify and correct ownership where needed.

Check ownership:

bash

ls -ld /home/newuser

If inconsistencies are found:

bash

sudo chown -R newuser:newuser /home/newuser

Verify the changes

bash

id newuser
getent passwd newuser

Ensure:

Username is updated
UID/GID remain unchanged
Home directory path is correct

IMPORTANT

Do not perform these changes while logged in as the target user
Always use root or another sudo-enabled account
Incorrect edits in /etc/passwd or /etc/shadow can break login functionality

For safer alternatives, consider using the usermod command as explained in Method 1.

Method 3: Change Username in Ubuntu (GUI Method)

This method applies only to systems running GNOME desktop (default in Ubuntu Desktop). It will not work on server editions or other desktop environments like XFCE or KDE.

Steps:

Go to Settings → Users
Unlock with administrator password
Create a new user with desired username
Transfer files from old user
Delete old user

Alternatively, use gnome-control-center:

bash

gnome-control-center users

NOTE

GUI method does not directly rename the user
It creates a new user instead

Method 4: Rename User in Active Session (Workaround)

Linux does not allow renaming a user while they are logged in. Attempting this results in:

bash

usermod: user olduser is currently used by process

Workarounds:

Kill active user processes:

bash

sudo pkill -u olduser

Or:

bash

sudo killall -u olduser

Then run:

bash

sudo usermod -l newuser -d /home/newuser -m olduser

Better approach:

bash

sudo reboot

Verify after rename:

bash

id newuser

Summary

Switching to GNOME on Linux depends on whether it is already installed and which desktop environment is currently active. You can quickly verify your current desktop using environment variables like XDG_CURRENT_DESKTOP and switch to GNOME from the login screen if it is available.

If GNOME is not installed, you can install it using your package manager and set it as the default session using system tools like update-alternatives. However, for most system administration tasks (such as user management), using terminal-based commands is preferred over GUI tools.