Some people here are already rather mean in their comments - imagine what would happen if I revealed The Magic CmdLine (TM)...
No, that privilege is reserved for the Inner Circle :-)
But I'll give you a teaser... It involved a lot of ImageMagick and "pdfimages" and "zxing" and "tesseract" and "pdfjoin" invocations... and the uploaded files were PDFs with scanned barcoded pages.
(I can imagine the gory details tbh - it sounds like there is every chance I have had a very similar command for a pretty similar purpose running for a good long while now... except mine's in a VBScript..!)
Across the road (on Reddit/programming), a commenter already described me pretty well:
"Everything about your (rather interesting) story... reaffirms everything I know about Linux sysadmins - if you encounter a problem, your go-to solution is to write a script ... Honestly, you guys would script a sandwich if you could :P"
The only thing wrong in that sentence, is that I am not a sysadmin (hence the knowledge of the Dark Arts - of GDB :-)