postgresql installation : initdb data directory not empty?

I am trying to create the postgresql database.

When I install PostgreSQL, I gave this command:

sudo yum install postgresql postgresql-server

and later I modified the config file:

sudo vim /var/lib/pgsql/data/pg_hba.conf

and modified as

local   all         all                               trust
host    all         all         127.0.0.1/32          trust
host    all         all         ::1/128               trust
host    all         all         0.0.0.0/0             md5

While I am trying to startup the postgresql service:

sudo service postgresql initdb

> Data directory is not empty!                               [FAILED]

sudo chkconfig postgresql on

sudo service postgresql start

Starting postgresql service:                               [  OK  ]

What is caused these errors and how do I fix them?

Initdb should only be run once. It will create the directory where you'll keep the config files and (usually) the actual database. You've obviously already done that already; otherwrise there wouldn't be any pg_hba.conf for you to edit.

So, just don't run postgresql initdb again, unless you are doing a complete reinstall.

From here:

If you're completely wiping & reinstalling a Postgres DB, when running initdb like:

service postgresql-9.2 initdb -E 'UTF8' --pgdata="/foo/bar/"

you can encounter this service error:

Data directory is not empty! [FAILED]

To fix it (and this is the nuclear option -- all db data is wiped!)

On Amazon Linux (2014-x):

rm -rf /var/lib/pgsql9/data

On CentOS (6.x)

rm -rf /var/lib/pgsql/9.2/data

Now try the initdb command again and it should work this time:

service postgresql-9.2 initdb