Log in postgres linux

How to login and authenticate to Postgresql after a fresh install?

There are two methods you can use. Both require creating a user and a database.

By default psql connects to the database with the same name as the user. So there is a convention to make that the «user’s database». And there is no reason to break that convention if your user only needs one database. We’ll be using mydatabase as the example database name.

Using createuser and createdb, we can be explicit about the database name,

$ sudo -u postgres createuser -s $USER $ createdb mydatabase $ psql -d mydatabase 

You should probably be omitting that entirely and letting all the commands default to the user’s name instead.

$ sudo -u postgres createuser -s $USER $ createdb $ psql 

$ sudo -u postgres psql postgres 

CREATE ROLE myuser LOGIN PASSWORD 'mypass'; CREATE DATABASE mydatabase WITH OWNER = myuser; 

$ psql -h localhost -d mydatabase -U myuser -p

$ grep "port log in" to the operating system as postgres. You're supposed to have root to get to authenticate as postgres.
  
It's normally not password protected and delegates to the host operating system. This is a good thing. This normally means in order to log in as postgres which is the PostgreSQL equivalent of SQL Server's SA, you have to have write-access to the underlying data files. And, that means that you could normally wreck havoc anyway.
  
By keeping this disabled, you remove the risk of a brute force attack through a named super-user. Concealing and obscuring the name of the superuser has advantages.