Installing postgreSQL on Linux

I compiled the PostgreSQL using the commands rpm -ivh *.rpm and installed it but as I want to install DSpace I have to follow the steps as follows

Once installed, you need to enable TCP/IP connections (DSpace uses JDBC). Edit postgresql.conf (usually in /usr/local/pgsql/data or /var/lib/pgsql/data), and add this line:

tcpip_socket = true

Then tighten up security a bit by editing pg_hba.conf and adding this line:

host dspace dspace 127.0.0.1 255.255.255.255 md5

Then restart PostgreSQL.

But I could not find the file postgresql.conf in either of the directory as suggested.

So I tried to erase the PostgreSQL using rpm -e *.rpm and it gave an error message that Postgre ... packages not installed

so I tried rpm -i *.rpm and its message was more shocking saying that its already installed.