This page explains how to connect `psql` to a PostgreSQL-dialect database in Spanner.
`psql` is the command-line front end to PostgreSQL.

1. Ensure that PGAdapter is running on the same machine as the `psql` command.

   For more information, see [Start PGAdapter](https://docs.cloud.google.com/spanner/docs/pgadapter-start.md.txt).
2. In a terminal window, start `psql` and specify `localhost` as the database server host.

   - Optionally specify a port number if PGAdapter is configured to listen on a port other than the default PostgreSQL port (5432).
   - Optionally specify one or more commands to send to the database or driver (for example, the JDBC driver). For each occurrence of the `-c` option, you can specify a single command or a batch of commands separated by semicolons (;). For more information, see [psql command-line tool](https://docs.cloud.google.com/spanner/docs/psql-commands.md.txt).

   `psql -h localhost [-p PORT] [-c "COMMAND; ..."] ...`
3. Optional: Verify that `psql` successfully connected to a PostgreSQL-dialect database
   by submitting the following query:

   `SELECT 1::bigint;`

   This query is incompatible with GoogleSQL-dialect databases.

## What's next

- Learn about [PGAdapter](https://docs.cloud.google.com/spanner/docs/pgadapter.md.txt).
- See the supported `psql` commands in [psql command-line tool](https://docs.cloud.google.com/spanner/docs/psql-commands.md.txt).