usermod - modify a user account
$ usermod [--append] [--uid uid] [--gid group] [--groups groups] [--lock] [--remove] [--unlock] [--home new-home] [--move] [--shell path-to-shell] [--gecos general-info] <username>This program modifies an existing user account. This program must be run as root.
--help: Display help message and exit--version: Print version-a, --append: Append the supplementary groups specified with the -G option to the user-u uid, --uid uid: The new numerical value of the user's ID-g group, --gid group: The group name or number of the user's new initial login group-G groups, --groups groups: Set the user's supplementary groups. Groups are specified with a comma-separated list. Group names or numbers may be used-L, --lock: Lock password-r, --remove: Remove the supplementary groups specified with the -G option from the user-U, --unlock: Unlock password-d new-home, --home new-home: The user's new login directory-m, --move: Move the content of the user's home directory to the new location-s path-to-shell, --shell path-to-shell: The name of the user's new login shell-n general-info, --gecos general-info: Change the GECOS field of the userusername: Username of the account to modify