It is a command-line tool that allows you to interact with a PostgreSQL database. It provides a powerful and flexible way to manage your databases, run queries, and perform various administrative tasks. Common commands in the PostgreSQL shell include: Running SQL queries: SELECT, INSERT, UPDATE, DELETE Creating and managing databases: CREATE DATABASE, DROP DATABASE Creating and managing tables: CREATE TABLE, DROP TABLE Manipulating data: INSERT, UPDATE, DELETE Querying data: SELECT Managing users and permissions: GRANT, REVOKE To access PostgreSQL shell, you can use a command-line interface (CLI) tool like Terminal or Git Bash, and run the command psql followed by the name of your PostgreSQL database and username. For example: psql mydatabase myuser. psql [option...] [dbname [username]]