Linux is a multi-user operating system. Each account on the system has a unique username. This is the name the user uses to log in to the system. It is also the name of the user's home directory. Every Linux distribution uses the "usermod" command to modify user accounts. This includes changing the user name for a particular account. The "usermod" command can only be used by the root user. The root user can modify every account that accesses the operating system.
Click on the main "Applications" or "Programs" menu.
Click on the "Terminal" or "Konsole" menu option to open a terminal window and access the command prompt.
Type the command "su -" to become the root user. Ubuntu and Linux Mint users type "sudo" before the following command.
Type the command "usermod -l new_user login" to change the user name for an account. Replace "new_user" with the new username for the account. Replace "login" with the current username for the account.
Type the command "exit" to close the root session.