Getting Started with PostgreSQLLesson 1.2

What is psql and how to use the psql command line tool

psql meta-commands, \l \c \dt \d, connecting to a database, quitting psql, SQL terminator

The psql CLI

psql is the official PostgreSQL interactive terminal. You will use it constantly — for running queries, inspecting schemas, and scripting migrations.

Connecting

psql -U postgres -d mydb -h localhost -p 5432

Flags: -U user, -d database, -h host, -p port. If you omit -d, psql connects to a database matching your username.

Key meta-commands

\l          -- list all databases
\c mydb     -- connect to a database
\dt         -- list tables in current schema
\d users    -- describe a table
\i file.sql -- execute a SQL file
\q          -- quit

Meta-commands start with a backslash and do not need a semicolon. Regular SQL statements must end with ; — psql buffers input until it sees one.

Useful shortcuts

\timing on  -- show query execution time
\x          -- toggle expanded output (wide rows)
\e          -- open query in $EDITOR

Use \? to list all meta-commands and \h SELECT to read the SQL syntax for any command. For scripting, pass -c for a single command or -f for a file: psql -U postgres -d mydb -f migration.sql.