composer

Install composer:

# Install
php composer.phar install

# Alternate install
# See: http://stackoverflow.com/questions/21670709/could-not-open-input-file-composer-phar-error-in-symfony2-using-wamp
curl -sS https://getcomposer.org/installer | php
mv composer.phar /usr/local/bin/composer

Update composer:

# Requires sudo to write
sudo composer self-update

Update packages:

# Update packages
php composer.phar update

# Update packages (with composer in $PATH)
composer update