Relational Data bases - Mario DataBase

I want to resume my work but seems not loading psql.

When I enter psql --username=freecodecamp dbname=postgres , the terminal shows:

psql: error: connection to server on socket “/var/run/postgresql/.s.PGSQL.5432” failed: No such file or directory
Is the server running locally and accepting connections on that socket?

After resuming tutorial it might be needed to start postgresql service. This can be done with following command:
sudo service postgresql start