Modify a user account. See also:
users
,useradd
,userdel
. More information: https://manned.org/usermod.
sudo usermod --login new_username username
sudo usermod --uid id username
sudo usermod --shell path/to/shell username
sudo usermod --append --groups group1,group2,... username
sudo usermod --move-home --home path/to/new_home username