Having logged in locally on a linux box, I used these steps to access the database via a terminal session …
$ sudo su - postgres [sudo] password for richard: ***** $ psql Password: ****** postgres=# postgres=# select version() PostgreSQL 9.4.4 on x86_64 (Red Hat 4.1.2-55), 64-bit
Line 1) As root, I switch to linux user “postgres” (including environmental variables)
Line 2) I typed in my password
Line 3) And ran the Executable (psql.exe)
Line 4) I typed in the password of the postgres user
Line 5) Success! and to prove it …
Line 6) My fist SELECT statement, lol
BTW: to leave I typed “\q” to quit the PostgreSQL environment, “exit” to leave the postgres account, then “exit” again to close the terminal session.