systemd units for automatically converting PDFs to PDFs to correct errors

Copy pdf2pdf to $HOME/bin. Copy pdf2pdf.path and pdf2pdf.service into $HOME/.config/systemd/user/. Reload user daemon:

systemctl --user daemon-reload

Then enable and start pdf2pdf.path:

systemctl --user enable pdf2pdf.path
systemctl --user start pdf2pdf.path

pdf2pdf.path monitors the directory $HOME/pdf for changes. If something changes the service unit is invoked which just executes pdf2pdf. pdf2pdf scans the directory $HOME/pdf for PDF files and converts them using pdftocairo. The bash script is configured to output the converted files to $(xdg-user-dir DOCUMENTS). After conversion the original file gets removed.