If 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
Thank you for putting up with my problem after a day of work suffering.