Assuming you  don't need to worry  about access control, ie  assuming the
lists are public, a more efficient way to do that is to:
 
1. Send  a 'select *  in listname' database  request to LISTSERV  to make
   sure the index is  up to date, and wait for  the answer. This normally
   takes very little time.
 
2. Link  to the disk with  the index and  write a pipeline that  builds a
   filelist from that.
 
  Eric