• To use postgresql, create a database instance and a user/role:

             sudo -u postgres createdb $USER

             sudo -u postgres createuser $USER

• Making both database instance and user/role as your login ID lets you to start PostgreSQL client very easily:

                     psql 

• To login as the administrator:

              sudo -u postgres psql

• To be able to login from remote machine or from PHP or through JDBC driver, you have to set your password from PostgreSQL client (psql):

              ALTER USER user PASSWORD 'pass';

• replace user and pass by your user name and password respectively. To test whether remote login works or not, run:

              psql -h host -p 5432 -d database -U user

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