Change user name and group name via ssh

1) Enable root login

sudo passwd root

2) exit, and re-ssh to the computer but login as root

3) usermod -l login-name old-name

1. move user dir cd /home mv old-name new-name

5) edit /ect/passwd to change the path of the user's home dir 

6) Change groupname

groupmod -n new_group_name old_group_name

7) exit, and re-ssh as the new-name, test if everything works

8) disable root account: 

sudo passwd -dl root