Tables, Charts, and Fields - Implementing Splunk: Big Data Reporting and Development for Operational Intelligence - page 65

This menu launches the Extract fields view:
In this view, you simply provide example values, and Splunk will attempt to build a
regular expression that matches. In this case, we specify ERROR , WARN , and INFO .
Under Sample extractions , we see that the values DEBUG , WARN , INFO , and
ERROR were matched. Notice that there are more values than we listed—the pattern
is looking for placement, not our sample values.
Under Sample events , we get a preview of what data was matched, in context.