How to run or call for a composer with Plesk's precompiled PHP?
Composer is a tool that helps find, install, and update library packages that your PHP project depends on. Libraries are installed in the project's root directory. The Composer utility is available as part of Plesk.
Plesk has already compiled PHP with all necessary modules. However, if it is necessary to install some additional modules to PHP supplied by Plesk, instead of default command:
# composer [options] [arguments]
use the following command:
# /opt/plesk/php/5.6/bin/php /usr/lib/plesk-9.0/composer.phar [options] [arguments]
Note: Only accounts with root privileges will be able to run composer