-bash-4.1$ initdb -D /var/lib/pgsql/data
The files belonging to this database system will be owned by user "postgres".
This user must also own the server process.

The database cluster will be initialized with locale en_US.UTF-8.
The default database encoding has accordingly been set to UTF8.
The default text search configuration will be set to "english".

initdb: directory "/var/lib/pgsql/data" exists but is not empty
If you want to create a new database system, either remove or empty
the directory "/var/lib/pgsql/data" or run initdb
with an argument other than "/var/lib/pgsql/data".
-bash-4.1$ rmdir /var/lib/pgsql/data
rmdir: failed to remove `/var/lib/pgsql/data': Directory not empty
-bash-4.1$ rm -rf /var/lib/pgsql/data
-bash-4.1$ initdb -D /var/lib/pgsql/data
The files belonging to this database system will be owned by user "postgres".
This user must also own the server process.

The database cluster will be initialized with locale en_US.UTF-8.
The default database encoding has accordingly been set to UTF8.
The default text search configuration will be set to "english".

creating directory /var/lib/pgsql/data ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 32MB
creating configuration files ... ok
creating template1 database in /var/lib/pgsql/data/base/1 ... ok
initializing pg_authid ... ok
initializing dependencies ... ok
creating system views ... ok
loading system objects' descriptions ... ok
creating conversions ... ok
creating dictionaries ... ok
setting privileges on built-in objects ... ok
creating information schema ... ok
vacuuming database template1 ... ok
copying template1 to template0 ... ok
copying template1 to postgres ... ok

WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the -A option the
next time you run initdb.

Success. You can now start the database server using:

    postgres -D /var/lib/pgsql/data
or
    pg_ctl -D /var/lib/pgsql/data -l logfile start

-bash-4.1$
-bash-4.1$ pg_ctl status
pg_ctl: server is running (PID: 10912)
/usr/bin/postgres "-D" "/var/lib/pgsql/data"
-bash-4.1$ psql
psql (8.4.7)
Type "help" for help.

postgres=# \df
                       List of functions
 Schema | Name | Result data type | Argument data types | Type
--------+------+------------------+---------------------+------
(0 rows)

postgres=#

pg_ctl -D /var/lib/pgsql/data -l logfile start