Use homebrew to upgrade to postgres on OSX

pg.sh

newpg=9.6.1 # set to new PG version number
oldpg=`pg_config --version | cut -d' ' -f2`

# PG 96. upgrades the readline to v7, which breaks anything linked against readline v6, like ruby via ruby-build. 
# I *think* this should prevent it from installing v7. But if weird shit happens with various rubies, 
# you'll have to reinstall them.
brew pin readline

# Stop current Postgres server
brew services stop postgresql

# Backup current db
mv /usr/local/var/postgres/ /usr/local/var/postgres-$oldpg

# Homebrew
brew update
brew upgrade postgresql

# Create new DB
initdb /usr/local/var/postgres -E utf8

# Upgrade old DB to new DB
mkdir -p /tmp/pgupgrade && cd $_
pg_upgrade \
  --old-datadir=/usr/local/var/postgres-$oldpg/ \
  --new-datadir=/usr/local/var/postgres \
  --old-bindir=/usr/local/Cellar/postgresql/$oldpg/bin \
  --new-bindir=/usr/local/Cellar/postgresql/$newpg/bin \
  --jobs=4

# Start new Postgres server
# launchctl load -w ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist
brew services start postgresql

# Clean new DB
./analyze_new_cluster.sh

# Make sure all your shit works!
# After determining upgrade successful you can remove old DB.
./delete_old_cluster.sh 
brew cleanup postgresql

# Go home
cd ~ 

Awesome... this worked very well! And I have no idea what I'm doing with Postgres.. not sure how one would upgrade without such clear instructions.

nice, thanks.

When upgrading from 9.0 to 9.2, I had to specify the new version of pg_upgrade, eg. /usr/local/Cellar/postgresql/9.2.3/bin/pg_upgrade . . .

homebrew had issues with the upgrade command; It told me that links with various names (various pg binary files) already exist. brew link --overwrite postgres fixed the problem.

I updated the script to be a bit more dynamic based on your suggestions, thanks guys!