Answers for "how to connect a database in postgresql with shell"

postgresql connect to database command line

user@user-pc:~$ sudo -i -u postgres
postgres@user-pc:~$ psql
psql (9.3.5, server 9.3.6)
Type "help" for help.

connecting to a new database using postgresql sql shell

For Windows users using the SQL shell

c DB_NAME USER_NAME HOST PORT

// to get the connection details such as your username, host and port simply use the "conninfo" command

eg : c test1 john_doe localhost 5432