A way to combine PDF files in UNIX and Linux
Published on 4th October 2008 Estimated Reading Time: 2 minutesMy latest adventure in the world of computing has led me into the world of automated PDF generation. When my first approach didn't prove to be completely trouble-free, I decided to look at the idea of going part of the way with it and finishing off the job with the open source utility Ghostscript. It is that which got me thinking about combining bookmarked PDF files and I can say that Ghostscript is capable of producing what I need as long it doesn't generate any errors along the way. Here's the command that does the trick:
gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=final.pdf source_file1.pdf source_file2.pdf
The various switches of the gs command have very useful roles with dBATCH ensuring that Ghostscript shuts down when all is done, dNOPAUSE removing any prompts that would otherwise be given, q for quiet mode, sDEVICE using Ghostscript's own PDF creation functionality and sOutputFile creates the output file, stopping Ghostscript from sending it to its default stream. All of this applies to Windows Ghostscript too, though the name of the executable is gswin32c for 32-bit Windows instead of gs.
When it comes to any debugging, it is useful to consider that Ghostscript is case-sensitive with its command line switches, something that I have seen to trip up others. I am getting initial device initialisation, so it strikes me that dropping some of the ones that reduce the number of messages might help me work out what's going on. It's a useful idea that I have yet to try.
There is also online documentation if you fancy learning more, and Linux.com has an article that considers other possible PDF combination tools as well. All in all, it's nice to have command line tools to do these sorts of things rather than having to use GUI applications all the time.
I have been using pdfsam for this. It's free, user friendly, and it works great, but I'm afraid it cannot be used directly from the command line like ghostscript.
I recently came across O'Reilly's PDF Hacks and that mentions quiet a few pieces of software and not just Ghostcript or anything that Adobe offers.