All Linux Things

Look here, https://itsfoss.com/merge-pdf-linux/

Thanks for pointing out pdfTricks. Working with pdfs in Linux is a pain point for sure. It would be nice to see the features incorporated into Okular and/or Evince. PDF has become such a common and standard format, it is almost essential to have tools readily available to manipulated them.

So to build on that, one of the big things I've found is that fillable forms nothing in most repos works REALLY well for it. Chrome/Chromium/Edge works ok for pdf's with fillable content, but still not perfectly. While it's not open source technology, master pdf editor (https://code-industry.net/masterpdfeditor/) is free for personal use, has downloads for .deb, .rpm, and standard .tgz for other distros, and is REALLY good with fillable forms. Technically there's far more it can do, however, I'm not sure how much is available in the free version (I literally just install it to use for fillable forms as I have a lot of them I use), or if it watermarks the resultant files in the free version, etc.

Thats why I posted it as Ive had many issues in Linux with pdfs versus Windows. The program tlmiller listed is indeed quite good and Ive used it before.
In Windows its a piece of cake as support is better. My hope is down the road all of this will improve further as I get a lot of pdf questions from Linux users.

Master PDF Editor. The free version 5 does watermark unless you buy. I still use V4 which was free and no watermarking. Can be a little buggy but does the job.