This article describes how to install Drush manually. Although shared and reseller hosting accounts include Drush by default, it is an older version that may not work with the most recent Drupal versions. For example, Drupal 8 requires Drush 8.
The Drush installation process uses composer, a PHP dependency manager. Therefore, if you have not already installed composer on your account, you must do so before installing Drush.
To install Drush on an account that has CageFS enabled, follow these steps:
composer global require drush/drush:dev-master
Type the following commands to add Drush to your path:
echo 'export PATH="$HOME/.composer/vendor/bin:$PATH"' >> ~/.bashrc source ~/.bashrc
Drush is now installed on your account.
Drush should display the most recent version number (at the time this article is written, version 8.1-dev is the latest version).
To update Drush to the newest version, type the following command:
composer global update
For more information about Drush, please visit http://drush.org.