Want to number pages in your Xournal journal files? If you’re using Xournal on a typical Linux distribution, you can try these Python scripts, which add or remove page numbers from the journal file itself.
They’re somewhat crude, so use them at your own risk. They create a new file rather than overwriting the old one, so the risk in using these should be minimal.
They have gotten the job done for me for at least a year now.
Any problems or suggested improvements? Let me know!