Drush not working properly on Ubuntu I am using Ubuntu 14.04 . When I try to download, enable, disable any module drush gives the following error:

Additional uncaught exception thrown while handling exception.OriginalDrupal\Core\DependencyInjection\ContainerNotInitializedException: \Drupal::$container is not initialized yet. \Drupal::setContainer() must be called with a real container. in Drupal::getContainer() (line 129 of /var/www/html/gitrepo/drupal/core/lib/Drupal.php).Drupal::getContainer()
drupal8_bootstrap(0)
_drush_bootstrap_drupal_configuration()
drush_bootstrap(3, 7)
drush_bootstrap_max()
drush_bootstrap_to_phase(-2)
Drush\Boot\DrupalBoot->bootstrap_and_dispatch()
drush_main()
AdditionalDrupal\Core\DependencyInjection\ContainerNotInitializedException: \Drupal::$container is not initialized yet. \Drupal::setContainer() must be called with a real container. in Drupal::getContainer() (line 129 of /var/www/html/gitrepo/drupal/core/lib/Drupal.php).Drupal::getContainer()
Drupal::theme()
_drupal_log_error(Array, 1)
_drupal_exception_handler(Object)
Drush command terminated abnormally due to an unrecoverable error.                                                                                             [error]
Sounds like you are not using the right version of Drush.  For Drupal 8.0-beta7, you need Drush 7.0.0-alpha9.  For Drupal 8.0-beta6, you need Drush 7.0.0-alpha8.

Drupal 8 APIs are changing rapidly; if you have mixed versions, you can easily encounter spurious problems.  Tracking HEAD of Drupal 8.0.x and Drush master is another viable strategy.