To augment the built-in commands, Splunk provides the ability to write commands in Python and Perl. You can write the commands to modify events, replace events, or even dynamically produce events.
While external commands can be very useful, if the number of events to be processed is large, or if performance is a concern, it should be considered a last resort. You should make every effort to accomplish the task at hand using the search language built into Splunk, or other built-in features. For instance, if you need:
regex, and extracted fields
splunk eval functionswith your favorite search ...