Installing Composer globally on CentOS 6.4
Composer is a PHP dependency manager. To install it globally on CentOS follow the steps below.
First, go to the /tmp directory
$ cd /tmp
Download the composer.phar file
$ curl -sS https://getcomposer.org/installer | php
Move it to /usr/local/bin/
$ mv composer.phar /usr/local/bin/composer
now you should be able to use the command composer
globally.