报错内容：
composer config -g repo.packagist composer https://mirrors.aliyun.com/composer
PHP Fatal error: Uncaught PharException: phar “/usr/local/bin/composer” has a broken signature in /usr/local/bin/composer:23
Stack trace:
#0 /usr/local/bin/composer(23): Phar::mapPhar(‘composer.phar’)
#1 {main}
thrown in /usr/local/bin/composer on line 23
是composer.phar文件损坏，重新下载即可
wget https://getcomposer.org/composer.phar