For those that haven't seen it the Splunk mug is a neat little piece of practical schwag that contains queries for things ranging from finding happiness to finding Waldo and even tracking a zombie infestation. However! I've discovered an issue with one of the searches.
The first thing to understand, if you don't already, is that the asterisk is a wildcard in Splunk. A neat little trick is that when you combine it with a field as in field=* your search will return events where that field contains a value. This makes it a great little inclusive search and potentially you won't have to use a usenull=f as part of your chart or timechart further in your search for filtering out events where the field isn't populated.
