composer.phar global require friendsofphp/php-cs-fixer
composer global require fabpot/php-cs-fixer
Then make sure you have ~/.composer/vendor/bin in your PATH and you're good to go
export PATH="$PATH:$HOME/.composer/vendor/bin"
php php-cs-fixer.phar fix /Applications/MAMP/htdocs/davidvandertuijn/app
php-cs-fixer fix /Applications/MAMP/htdocs/davidvandertuijn/app