Export long iPhone message conversation via command line to PDF or HTML?

I'm looking to use the command line (Terminal or iTerm2) to export a long conversation to PDF or HTML in monthly chunks. I want to be able to do this regularly so I can make a regular backup and maybe I can find a nice pretty way to display it on the web or via Google Drive or Dropbox. Who knows.. If I have to write some code to do that, I think I can handle it. According to my research, those chat messages are stored as an SQLite database hidden somewhere in the application data directories for the 'Messages' application. Are there any existing tools for this? I suspect because the SQLite method I mentioned is not an "official" way to access that data, it's likely not published on the web anywhere? I've tried some of the commercial products but they are okay at best. Would like to get to the raw data if I can. Out of the commercial projects I've tried: * iExplorer * PhoneView * Decipher TextMessage At this point I tried using iExplorer to export one huge PDF (2.5k pages). What I would ideally want (and what this question is asking for) is to be able to run a regular job via Terminal to update the HTML or PDF representation of the chat log. UPDATE: For anyone else who has the same problem, I've been using iExplorer which apparently does work it just takes FOREVER because my file is huge. I want something that's iterative so I can run this process on a regular basis.