Create a user account for the PostgreSQL server. This is the user the server will run as. For production use you should create a separate, unprivileged account (“postgres” is commonly used). If you do not have root access or just want to play around, your own user account is enough, but running the server as root is a security risk and will not work.

adduser postgres

Create a database installation with the initdb command. To run initdb you must be logged in to your PostgreSQL server account. It will not work as root.

root# mkdir /usr/local/pgsql/data
root# chown postgres /usr/local/pgsql/data
root# su - postgres
postgres$ /usr/local/pgsql/bin/initdb -D /usr/local/pgsql/data

The -D option specifies the location where the data will be stored. You can use any path you want, it does not have to be under the installation directory. Just make sure that the server account can write to the directory (or create it, if it doesn't already exist) before starting initdb, as illustrated here.

At this point, if you did not use the initdb -A option, you might want to modify pg_hba.conf to control local access to the server before you start it. The default is to trust all local users.

The previous initdb step should have told you how to start up the database server. Do so now. The command should look something like:

/usr/local/pgsql/bin/postgres -D /usr/local/pgsql/data

This will start the server in the foreground. To put the server in the background use something like:

nohup /usr/local/pgsql/bin/postgres -D /usr/local/pgsql/data \
    </dev/null >>server.log 2>&1 </dev/null &

To stop a server running in the background you can type:

kill `cat /usr/local/pgsql/data/postmaster.pid`

Create a database:

createdb testdb

Then enter:

psql testdb

to connect to that database. At the prompt you can enter SQL commands and start experimenting.