Which command is used to add users to or from existing roles?

 The command to add users to or from existing roles is add rba user roles . This command allows you to assign one or more roles to a user in the Gaia database. Roles are collections of permissions that define what actions a user can perform on the system. You can use predefined roles or create your own custom roles. To remove a role from a user, you can use the command delete rba user roles .