composer/composer — Issue #55: Add --global option to install packages in $PATH bin dir and global code dir (e.g. /usr/share/composer)
Author: naderman
Created: 2011-10-22 12:19:51+00:00
State: open

It should work like npm's option http://npmjs.org/doc/faq.html#How-do-I-install-something-everywhere

Globally installed packages will neither be in include_path nor in autoloaders of projects. If you want to install a dependency for a project, install it locally.

The only reason to install a package globally is to get some global commandline utility.