This is a very simple Nagios plugin that checks on items in an OpenHAB instance. It uses OpenHAB's REST API.
The plugin can retrieve the state of an item and either compare it numerically to critical and warning thresholds or treat the state as a string and match patterns against it.
The plugin requires Python version 2.6 or later on the testing system and python-dateutil.
The help function (check_openhab --help) should cover everything you
need to know.