Composer をインストールする 2 つの方法

curl -sS https://getcomposer.org/installer | php

php -r "readfile('https://getcomposer.org/installer');" | php

curl -sS https://getcomposer.org/installer | php -- --install-dir=bin

curl -sS https://getcomposer.org/installer | php   //获取composer
mv composer.phar /usr/local/bin/composer   
composer   //直接运行composer

vi /etc/profile 
export PATH=/usr/local/php5.6/bin/:/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin
source /etc/profile (or environment) # 让环境变量立即生效