Argument #8 provides the location of a file with the results of the search. The file keeps the search results is in gzip compressed format. At this point you have two choices: 1) you can read the contents of that file or 2) pass the entire file to your script.
Let us assume that you are working in a UNIX/Linux environment and that you want to pass the contents of the results file to a third-party program. At this point you will use the shell wrapper to pass the results variable and let the third-party program deal with the data set.
$perlExec $perlScript "$results"
On the other hand, you may be working in MS Windows and you may want to pass the entire file to another program. The alert function allows you to use a BATCH program as a wrapper and then you would pass the right content to a third-party program. If that were the case, you might use something like this:
%POWERSHELL% -file %SCRIPT% "%SPLUNK_ARG_8%"
Of course there are many other variations of these types of use so judge these examples as basic illustrations.