Had to install Yarn (
brew install yarn). Already had composer installed. Needed to upgrade my local version of php:
curl -s http://php-osx.liip.ch/install.sh | bash -s 7.0
Then point to it for php-cli:
export PATH=/usr/local/php5/bin:$PATH to
source ~/.bashrc, which is the file named
.bashrc in my home directory.