CentOS 7 へインストール

https://kohkimakimoto.github.io/getcomposer.org_doc_jp/doc/00-intro.html を参照して、

# curl -sS https://getcomposer.org/installer | php
# mv composer.phar /usr/local/bin/composer
# composer --version
Do not run Composer as root/super user! See https://getcomposer.org/root for details
Composer version 1.5.2 2017-09-11 16:59:25