We have a bunch of scripts to generate invoices for our customers. It creates plain TeX files from CSV and then PDF files (using the
pdftex program). This "black box" was created by one of our former employee. Frankly, I don't understand TeX or plain TeX at all.
Recently, we added customer that has underscore character in his address. The "black box" stopped working until I googled up, that I have to escape underscore characters like this:
Scripts are working well again, but a new problem occurred. When I copy & paste the text from final PDF (to email or text editor or somewhere else), the underscore characters disappears (they are replaced with spaces
In Acroread or other PDF viewers they are displayed properly. They just cannot be "copied out". It looks like in PDF it is some other character than in other fonts.