最简单的方案:
sudo curl -sS https://getcomposer.org/installer | sudo php sudo mv composer.phar /usr/local/bin/composer
安装完后最好更新一下:
composer self-update
参考列表
官网 https://getcomposer.org/download/
Install PHP Composer In Ubuntu http://segmentfault.com/a/1190000000417603