Import SQL file to PostgreSQL in container

Import_SQL_file_to_PostgreSQL_in_container.sh

# Single quotes are relevant to delay expansion to be executed in container shell session
# 1. using docker exec: 
cat /path/to/file.sql | docker exec -i <running postgres container name> \
    bash -c 'PGPASSWORD=${POSTGRES_PASSWORD} psql -U ${POSTGRES_USER} -d ${POSTGRES_DB}'
# 2. using docker compose exec
cat /path/to/file.sql | docker compose exec -i <service name in docker-compose.yml> \
    bash -c 'PGPASSWORD=${POSTGRES_PASSWORD} psql -U ${POSTGRES_USER} -d ${POSTGRES_DB}'
# You can also use `docker compose exec`:
# docker compose exec -i <service name in docker-compose.yml> bash -c '...' < /path/to/file.sql