I installed version 9.1 in my Ubuntu OS, but not able to login.
What is default password for user Postgres?
The postgres user doesn't have a password by default, which is probably how you should keep it. Typically the pg_hba.conf file (which you'll find in /etc/postgresql/9.1/main/pg_hba.conf) contains an entry like:
local all all trust
So reading from left to right, this allows local connections to all databases for all users using trust authentication, meaning it will believe you're the postgres user if you say you are, and can be trusted, as long as you're connecting over a local connection (i.e. using a unix domain socket). So become the postgres user:
sudo su - postgres
and then you should just be able to connect to the database without any issues:
postgres@swift:~$ psql postgres postgres psql (9.3.1) Type "help" for help.
