Using psql to connect to PostgreSQL in SSL mode

psql --set=sslmode=require -h localhost -p 2345 -U thirunas \
-d postgres -f test_schema.ddl

Another Example for securely connecting to Azure's managed Postgres database:

psql --file=product_data.sql --host=hostname.postgres.database.azure.com --port=5432 \
--username=postgres@postgres-esprit --dbname=product_data \
--set=sslmode=verify-full --set=sslrootcert=/opt/ssl/BaltimoreCyberTrustRoot.crt.pem

psql below 9.2 does not accept this URL-like syntax for options.

The use of SSL can be driven by the sslmode=value option on the command line or the PGSSLMODE environment variable, but the default being prefer, SSL connections will be tried first automatically without specifying anything.

Example with a conninfo string (updated for psql 8.4)

psql "sslmode=require host=localhost dbname=test"

Read the manual page for more options.

Found the following options useful to provide all the files for a self signed postgres instance

psql "host={hostname} sslmode=prefer sslrootcert={ca-cert.pem} sslcert={client-cert.pem} sslkey={client-key.pem} port={port} user={user} dbname={db}"