multi_nagios could be run on the with -r /--root supplied Drupal installation to check for core updates.
or
on a the with -l / --uri supplied site to check for core and module updates
drush -r /path/to/drupal multi-nagios
DRUPAL ROOT CRITICAL: drupal-6.13 @ /path/to/drupal
- drupal-6.14 (2009-09-16 21:40) available, see http://drupal.org/node/579476 for details.
Or if we are running the recommended version:
DRUPAL ROOT OK: drupal-6.14 @ /path/to/drupal/6.x is uptodate.
drush -r /path/to/drupal multi-nagios --file=/path/to/file
drush -r /path/to/drupal -l example.com multi-nagios
DRUPAL SITE OK - example.com @ /path/to/drupal/example.com: All modules are uptodate.
If there are available updates, it might produce the following output:
DRUPAL SITE CRITICAL - example.com @ /path/to/drupal/sites/example.com: there are updates for admin_menu,drupal,image, see http://example.com/?q=admin/reports/updates for datails.
1.5.8