Installing Composer Globally on CentOS 6.4
Composer requires PHP 5.3.2+ to run. A few sensitive php settings and compile flags are also required, but the installer will warn you about any incompatibilities.
To install it globally on CentOS follow the steps below.
1. First, go to the /tmp directory.
[root@centos ~]# cd /tmp
2. Download the composer.phar file.
[root@centos tmp]# curl -sS https://getcomposer.org/installer | php
3. You can run these commands to easily access composer from anywhere on your system: Move it to /usr/local/bin/
[root@centos tmp]# mv composer.phar /usr/local/bin/composer
4. Then, just run composer in order to run Composer instead of
[root@centos ~]# php composer.phar
Reference URL : https://getcomposer.org/doc/00-intro.md