brew-upgrade.sh

#!/usr/bin/env bash

sudo -v
trap 'echo "Something went wrong, restart script to retry"' ERR

set -ex
export PATH=/usr/bin:/bin:/usr/sbin:/sbin

downloadPkg() {
        echo "Downloading $1..."
        /usr/local/bin/brew fetch --retry "$1" > /dev/null
        echo "Finished downloading $1"
}

if ! [ -f ~/.brew-upgrade ] && [ -n "$(which brew)" ];then
        brew list -1 > ~/.brew-upgrade
fi

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall)"
if [ -e ~/.gem ];then
  mv ~/.gem ~/.gem-brew-upgrade
fi
sudo rm -rf /usr/local/Cellar /usr/local/Homebrew /usr/local/Caskroom
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

if [ -f ~/.brew-upgrade ];then
        find -L /usr/local/bin -name . -o -type d -prune -o -type l -exec rm {} \;
        find -L /usr/local/sbin -name . -o -type d -prune -o -type l -exec rm {} \;
        for pkg in $(cat ~/.brew-upgrade);do
                downloadPkg "$pkg" &
        done
        wait
        for pkg in $(cat ~/.brew-upgrade);do
                if ! /usr/local/bin/brew install -f "$pkg";then
                        echo "Brew reinstalation failed, press enter to continue or ctrl+c to abort, you will be able to rerun this script to try again"
                        read
                fi
        done
        rm -f ~/.brew-upgrade
fi


if [ -e ~/.gem-brew-upgrade ];then
  rm -rf ~/.gem
  mv ~/.gem-brew-upgrade ~/.gem
fi