It pipes, therefore it is

This is crucial. Everything else about the package is clear once this is grasped. This is not a reduction package like CGS4DR; it is a reduction black box which knows the incoming data types (by their headers) and transparently applies a reduction recipe to them. There is nothing preventing you from running three simultaneous instances of the pipeline, for example to (i) reduce the incoming data in real time, (ii) re-reduce a previous group of files using a different reduction recipe and (iii) reduce and file a single previous observation as a dark. You do this by running three versions of oracdr, using the command-line switches to alter their behavior (recipe, start and end observation numbers to process, graphics options, etc.). Each instance of the pipeline will go through the required files (existing ones or files just arriving on disk as specified on the command line) and reduce them. Once its remit of reduction is complete, it will exit.