Mac Homebrew upgrade postgres from 9.2.4 to 9.3.0

update_postgresql.sh

# Unload the launch_ctl (stop the server)
launchctl unload ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist

# Move the data directory
mv /usr/local/var/postgres /usr/local/var/postgres92

# Upgrade postgresql
brew update && brew upgrade postgresql

# Init the new database cluster
initdb /usr/local/var/postgres -E utf8

# Update the old database cluster to the new one
pg_upgrade -b /usr/local/Cellar/postgresql/9.2.4/bin -B /usr/local/Cellar/postgresql/9.3.0/bin -d /usr/local/var/postgres92 -D /usr/local/var/postgres

# Load the launch_ctl (start the server)
launchctl load ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist

# For each ruby, uninstall the pg gem
gem uninstall pg

# export ARCHFLAGS env var
export ARCHFLAGS="-arch x86_64"

# For each rails project using pg, reinstall the gem
bundle install

# Verify it works
rails c

# Profit

Thanks for this!

I've posted a few more details here http://tautt.com/upgrading-postgresql-9-2-to-9-3/ :)