I have Drush 7.x installed and when I run 'drush up', on a Drupal 7.x codebase, I get the following error:
Drush command terminated abnormally due to an unrecoverable error.
[error]Error: require_once(): Failed opening required '/home/user/public_html/core/includes/install.inc'
It seems like Drush 7.x may be looking for Drupal 8.x file structure. How should I be running this command?