usermod

Change username

$ sudo usermod -l new_username username

$ sudo usermod -u 1001 username

$ sudo usermod -s /bin/zsh username

$ sudo usermod -aG group1,group2 username

$ sudo usermod -rG group1,group2 username

$ sudo usermod -m -d /new/home username

$ sudo usermod -L username

$ sudo usermod -U username

usermod [options] LOGIN

usermod modifies system account files to change user account attributes. It can update username, user ID, groups, home directory, shell, and account status.

-a, --append

Append to supplementary groups (use with -G)

Change the comment field (GECOS)

Set new home directory

Set account expiration date (YYYY-MM-DD)

Days after password expires until account disabled

Change primary group

Set supplementary groups (replaces existing)

Change username

Lock the user account

Move home directory contents to new location

Set encrypted password

Remove user from specified groups (use with -G)

Change login shell

Change user ID

Unlock the user account

Set SELinux user mapping

When changing UID, files owned by the user need to be manually updated. Use -a with -G to add groups without removing existing ones. The user must not have running processes when changing username.

usermod is part of the shadow-utils package for managing user accounts on Unix-like systems.

useradd(8), userdel(8), passwd(1), groupmod(8)