psql, I try to connect to a database and I get "psql: FATAL: Peer authentication failed for user ", why?

I'm using **psql (9.2.23)** on my Dell Latitude 3540 laptop running **Linux CentOS 7**. I want to do a simple thing: create a database username and log in as that username. My operating system username is "davide", and the username I'd like to create and use in psql is "davide3". My laptop name is "laptop". Here are the steps I followed, after having installed PostgreSQL: > [davide@laptop ~]$ sudo su - postgres > > [sudo] password for davide: > > Last login: XXX > > -bash-4.2$ psql > > psql (9.2.23) > > Type "help" for help. > > `postgres=# CREATE USER davide3 WITH PASSWORD 'davide3' CREATEDB > CREATEUSER;` > > CREATE ROLE > > postgres=# \q > > -bash-4.2$ exit > > logout Then I try to login to the database by using the username "davide3": > [davide@laptop ~]$ psql -d postgres -U davide3 > > psql: FATAL: Peer authentication failed for user "davide3" Here's the trouble: I was expecting to get a password-insertion message, and to insert the 'davide3' password, but I did not get anything instead. **What did I do wrong? How to solve this issue?** Thanks