I want to change some Text-Coloring by regex search in one or more PDFs. for example i want to change the color of all appearances of "A[0-9]+.[0-9]" like A120.1, A600.0 and so on. is it even possible to change specific text colors in a PDF. a command line solution would be nice, I don't care if win or linux - both would be ok Thank you in advance for suggestions.