Installation of Postgres in ubuntu 14.04

sudo apt-get install postgresql postgresql-contrib

sudo -i -u postgres//authenticate as postgres user

sudo -u user_name psql db_name//or u can use this to login directly

psql

createdb test//create db with name as test

\dt //to know tables in db

alter user user_name with password 'new_password';//chage user name delete psql history after query