I am officially an old person, as I have subscribed to a magazine. It’s niche, but it’s been around a long time, and having enjoyed a lot of issues in my childhood that were given to me for free, I feel I should give back.

I’m wondering if there are precautions I should take. Can any sort of copy protection be put into PDFs that I should strip out? If I share them as a torrent, should I be worried that the publisher can tell where they came from?

  • GenderNeutralBro@lemmy.sdf.org
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    10 months ago

    There are some free, open-source command line tools that can do this.

    First off, there’s exiftool. It’s the go-to utility to read and write metadata in a wide variety of file types, like mp3, jpg, and you guessed it, pdf. It’s very easy to use:

    To read all the metadata in a file: exiftool -a -All (where is the path to your pdf).

    To erase all the metadata in a file: exiftool -a -All="" (that’s two double-quotes, to indicate a blank string). Please note that this will overwrite your file in-place! If you want to save the output as a new file, use exiftool -a -All="" -o .

    exiftool is likely all you need for your use case, but if you need more advanced PDF manipulation, with a truly dizzying array of options, there’s Ghostscript. Ghostscript can read, write, and convert PDFs, and provides hooks to apply any PostScript commands and options.

    To simply print out information on a PDF file: gs -dPDFINFO -dBATCH . This will show you the metadata, such as author, title, etc.

    I’m…not going to give you an example of how to use Ghostscript to edit metadata because I’m not confident I’d get it right. The gist is that you use PostScript commands with the -c flag. It is truly arcane but extraordinarily powerful.

    If you’re on Linux, you can likely get both of these with your distro’s default package manager. On Mac, use Homebrew or MacPorts. On Windows, you can download prebuilt binaries from their web sites. I think you can even run them on Android using Tmux Termux.

    • drivepiler@lemmy.world
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      10 months ago

      I believe you’re referring to Termux, the terminal app. Tmux is a terminal multiplexer. Although you can run Tmux in Termux, so technically…

      Anyway, great post! It seems I have to check out Ghostscript, don’t think I’ve ever heard of it, thanks.