Connect to PostgreSQL Databases

The psql command is the interactive terminal for PostgreSQL, allowing you to connect to databases, execute SQL queries, and manage your database instances directly from the command line. It's an essential tool for developers and database administrators working with PostgreSQL.

Basic Connection and Usage

To connect to a database on the local machine using the default port (5432) and the current operating system user, simply use:

psql database_name

Advanced Connection Options

For more specific connections, you can specify the host, port, and username. To connect without a password prompt:

psql -h host_address -p port_number -U username database_name

If you need to be prompted for a password:

psql -h host_address -p port_number -U username -W database_name

Executing SQL Commands and Scripts

psql is versatile and can execute single SQL queries or entire scripts. To execute a single query directly:

psql -c 'SELECT version();' database_name

To run commands from a SQL file:

psql database_name -f your_script.sql

Related PostgreSQL Tools

When working with PostgreSQL, other useful command-line utilities include:

• pg_dump: For backing up PostgreSQL databases.
• pg_restore: For restoring PostgreSQL databases from backups.
• pg_top: A utility to monitor PostgreSQL processes.

For more information and resources on PostgreSQL and psql, explore PostgreSQL cheat sheets and documentation.