$ psql -U <username>

List databases (after logged in)

\l

Quit psql

\q

Connect to a database

\c <db>

Show current db

SELECT current_database();

List schemas

\dn

Tables

List tables

\dt *

Get table definition

\d <table>

Get even more about a table

\d+ <table>

Other objects

List functions

\df

List indexes

\di

List data types (useless without +)

\dT+

List views

\dv