To change the username of an already created account on a UNIX or Linux system just follow this simple guide.
I am changing the username mailman to mailman2. Firstly; open the /etc/shadow file with the VIM editor.
homer@deep-thought ~ % sudo vim.tiny /etc/shadow
Then find the entry you are after and edit the name and then press ESC and type :wq to save and quit the editor.
Then open the /etc/passwd file and change that value as well.
homer@deep-thought ~ % sudo vim.tiny /etc/passwd
Leave the /home folder value as is of course; but this will work very well to enable you to
After all of this you can use the /bin/login command to test whether the newly renamed account works or not. And it worked perfectly.
homer@deep-thought /home % sudo login deep-thought login: mailman2 Password: Last login: Thu Jul 25 19:37:06 EST 2013 on pts/0 Welcome to Linux Mint 15 Olivia (GNU/Linux 3.8.0-26-generic x86_64) Welcome to Linux Mint * Documentation: http://www.linuxmint.com mailman2@deep-thought ~ $ pwd /home/mailman