Since PostgreSQL 8.1, the concepts of users and groups have been unified into a single kind of entity called a role. Notes. The REVOKE command is used to revoke access privileges.. Create a user with the command line. You can also create a user by using the command-line wrapper called createuser - this method is more convenient for programmers and administrators who have access to the console of the respective PgSQL server and only have to execute a single command instead of logging in and using the interface of the respective PostgreSQL client.