How do I change my username?

Question

Some time ago, when I installed Ubuntu, I chose a rather stupid username for my account that I do not want to use anymore.

How do I change this (including the name of my home directory, and the name in the terminal) without losing settings for applications?
How do I keep permissions and my keys for various authentification (e.g. email, SSH, GPG and more)?
What settings could possibly get lost if I changed my username?

Answer 1

Unix-like operating systems decouple the user name from the user identity, so you may safely change the name without affecting the ID. All permissions, files, etc are tied to your identity (uid), not your username.

To manage every aspect of the user database, you use the usermod tool.

To change username and user's groupname (it is probably best to do this without being logged in):

sudo usermod -l newUsername oldUsername
sudo groupmod -n newUsername oldUsername

This however, doesn't rename the home folder.

To change home-folder, use

sudo usermod -d /home/newHomeDir -m newUsername

after you changed the username.

For instance, you could logout, drop to a console (Ctrl+Alt+F1), and sudo su - to become true root (as opposed to sudo -s, where $HOME is still /home/yourname.) Maybe you also have to kill some still running processes from this user first. To do so, enter ps -u username, look for the matching PID and kill them by kill PID-number.

Update: as arrange mentioned, some files may reference your old home directory. You can either keep a symlink for backward compatibility, e g ln -s /home/newname /home/oldname or you can change the file contents with sed -i.bak 's/*oldname*/*newname*/g' *list of files* It creates a backup for each file with a .bak extension.

Some additional information for not so experienced users like me:
As I only have ONE user account (administrator), it would not let me change the username ("you are already logged in" was the response in TTY1 (Ctrl+Alt+F1). To get around this:

1. Login with your old credentials and add a new user, e.g. "temporary" in TTY1:

   sudo adduser temporary
   

set the password. 2. Allow the temporary user to run sudo by adding the user to sudo group:

    sudo adduser temporary sudo

3. Log out with the command exit.

4. Return to tty1: Login with the 'temporary' user account and password. Change your username and folder as mentioned above. exit (until you get the login prompt)

5. Go back to TTY7 (Ctrl+Alt+F7) to login on the GUI/normal desktop screen and see if this works.

6. Delete temporary user and folder:

   sudo deluser temporary
   sudo rm -r /home/temporary
   

Answer 2

To put it all together:

1. Log out of your session or restart your computer to get back to the start screen.

2. At the start screen go to a console mode tty. Press Ctrl+Alt+F1 (on some Ubuntu revisions this may be Ctrl+Alt+F2 instead)

3. Log in using your username and password.

4. Set a password for the "root" account.

    sudo passwd root
   

5. Log out.

    exit
   

6. Log in using the "root" account and the password you have previously set.

7. Change the username and the home folder to the new name that you want.

    usermod -l <newname> -d /home/<newname> -m <oldname>
    usermod -c "newfullname" <newname>
   

   "newfullname" is the fifth column in /etc/passwd, and might be "First Last", for instance.

8. Change the group name to the new name that you want.

    groupmod -n <newgroup> <oldgroup>
   

9. Lock the "root" account so it no longer has a valid password that can be used to log in as root.

    passwd -l root
   

10. If you were using ecryptfs (encrypted home directory). Mount your encrypted directory using ecryptfs-recover-private and edit <mountpoint>/.ecryptfs/Private.mnt to reflect your new home directory.

11. Log out.

    exit
    

12. Press Ctrl+Alt+F7 to go back to the Ubuntu graphics mode login screen (on some Ubuntu revisions this may be Ctrl+Alt+F1).

And now you can log in using your new username.

Answer 3

Restart in recovery mode and go to the root prompt shell ("Drop to root shell prompt")

First remount the root

mount -o remount,rw /

To change the username and home folder name,

usermod -l <newname> -d /home/<newname> -m <oldname>

For group name,

groupmod -n <newgroup> <oldgroup>

Answer 4

On Ubuntu 13.10, 14.04, 16.04:

1. Click on the "System Settings" icon.
2. Click on "User Accounts".
3. Your administrator account should be displayed.
4. Click on the "Unlock" button.
5. Enter your user password as requested to allow changes to your account.
6. Once unlocked, you can click on your old user name that you wish to change and type in a new user name to replace it.
7. When you have typed in the new name, click on the "Lock" button to make the change permanent.
8. Restart Ubuntu.

Answer 5

When receiving usermod: can't change /etc/password just run the following commands:

In the root recovery console run:

mount -o remount,rw /

Then rerun:

usermod -l <newname> -d /home/<newname> -m <oldname>

Answer 6

The answer listed here by @karthick87 works perfectly fine but here is what I would do just to be safe and avoid all glitches:

1. Create a separate account/user and make sure this account/user root capabilities or login as any root-able user.
2. Logout with the current account and then login with the account mentioned in step 1.
3. Kill all the processes of the previous user.
4. Now follow the steps mentioned by @karthick87 and change username and also the home directory owner.
5. Then follow @Sriraj Hebbar's answer to change the group name.
6. logout with the spare user and login with your user. If you created an extra user delete it.

Answer 7

when you do usermod -l <newname> -d /home/<newname> -m <oldname> you will get useradd: can't change /etc/passwd error message to avoid this just add sudo -- to above command like

sudo -- usermod -l <newname> -d /home/<newname> -m <oldname>

and

sudo --  groupmod -n <newgroup> <oldgroup>

Answer 8

Since not all the linuces (however Ubuntu must have it) have the usermod app, there is the way you can do it manually. As of root open /etc/passwd to edit with vim or any other editor presening in the system:

sudo vim /etc/passwd

and change the user's name at the beginning of a line:

user:x:500:501:username:home/user:/bin/bash

to:

newuser:x:500:501:username:home/user:/bin/bash

then if you worked of root just login, and if you have been logged in as a user, logoff, and relogin.

Of course you have to fix /etc/shadow, and /etc/group also to the system works properly. Thanx to @JohanBoulé

NOTE: You should use this approach carefully, to not break the system.

NOTE: This approach is common, not only for Ubuntu, but and for ubuntu it will work, however google search will show it event for non ubuntu search, for example for embedded linux