psql is a terminal-based front-end to PostgreSQL. It enables you to type in queries interactively, issue them to PostgreSQL, and see the query results. Alternatively, input can be from a file.[1]
Launch Interactive session
psql -h localhost -U postgres -d somedb
connect to local database i.e.(username = postgres, database name = postgres)
sudo -u postgres psql -d postgres
Connection options:
-h, --host=HOSTNAME database server host or socket directory
-p, --port=PORT database server port number
-U, --username=NAME connect as specified database user
-W, --password force password prompt (should happen automatically)
-e, --exit-on-error exit on error, default is to continue
-d DBNAME some database
connect to database dbname_db with user name = postgres:
\c dbname_db postgres
change a user's password:
ALTER USER username WITH PASSWORD 'mypassword';
create db
CREATE DATABASE db_name;
grant privileges to user
GRANT ALL PRIVILEGES ON DATABASE db_name TO user_name;
reference:
[1]https://www.postgresql.org/docs/9.4/static/app-psql.html
[2]https://www.postgresql.org/docs/9.2/static/sql-alterrole.html
