升级的方法很简单，就是先卸载后安装： # you need to first remove the composer sudo apt-get remove composer # ubuntu install composer php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');" # and then type the below command to install composer globally sudo php composer-setup.php --install-dir=/usr/local/bin --filename=compo… Read More