Testing user exit utilities can be challenging. The easiest way to do this is to use one of the DOS batch files generated for each enabled user exit during a BRP run. These files will contain all the parameters and the values can be changed to suit the needs of the testing requirements. Replace the last command in the file with whatever command is necessary. In a Perl context we would use:
perl -d myUtility.pl
Note that a DOS command window will not execute one of these generated batch files when they have same filename the BRP run assigns (for example, (timestamp)UserExit.bat). This is due to some intrinsic interpretation of the leading "(timestamp)" in the file name. Simply delete this portion of the file name and the batch file will work normally.