Postgresql: show tables, show databases, show columns

PostgreSQL is one of the best database engines for an average web project and many who moves to psql from mysql (for example) often ask the following questions: what  is the analog of “show tables” in postgres? or how can I get the list of databases in postgres like “show databases” in mysql? The answers are short:
mysql: SHOW TABLES
postgresql: \d
postgresql: SELECT table_name FROM information_schema.tables WHERE table_schema = 'public';
mysql: SHOW DATABASES
postgresql: \l
postgresql: SELECT datname FROM pg_database;
mysql: SHOW COLUMNS
postgresql: \d table
postgresql: SELECT column_name FROM information_schema.columns WHERE table_name ='table';