With the advent of Drupal 8 and composer integration, there is a better way of installing Drush.
Install Composer:
curl -sS https://getcomposer.org/installer | php
Enable Composer access for All Users:
mv composer.phar /usr/local/bin/composer
ln -s /usr/local/bin/composer /usr/bin/composerInstall Drush:
git clone https://github.com/drush-ops/drush.git /usr/local/src/drush
cd /usr/local/src/drush
git checkout 6.x // 7.x or whatever version you want.
ln -s /usr/local/src/drush/drush /usr/bin/drush
composer install
drush --version--
Source
http://docs.drush.org/en/master/install/
Technologies: