hot to modify user group ubuntu

To modify an existing user, like adding that user to a new group, use the usermod command.

Try this:

sudo usermod -a -G groupName userName

The user will need to log out and log back in to see their new group added.

• The -a (append) switch is essential. Otherwise, the user will be removed from any groups, not in the list.
• The -G switch takes a (comma-separated) list of additional groups to assign the user to.