Start/Stop PostgreSQL on Mac

Start PostgreSQL:-

sudo -u postgres /Library/PostgreSQL/9.3/bin/pg_ctl -D /Library/PostgreSQL/9.3/data start

Stop PostgreSQL:-

sudo -u postgres /Library/PostgreSQL/9.3/bin/pg_ctl -D /Library/PostgreSQL/9.3/data stop

Stop PostgreSQL from auto-starting on reboot:-

sudo launchctl unload -w /Library/LaunchDaemons/com.edb.launchd.postgresql-9.3.plist 

Make PostgreSQL auto-start on reboot:-

sudo launchctl load -w /Library/LaunchDaemons/com.edb.launchd.postgresql-9.3.plist 

Refs
http://www.xtuple.org/faq/xtuple-faq/postgresql/how-do-i-stop-postgresql-service-mac 
https://gist.github.com/abhishekdev/1960888