zusammenführen von seiten:pdftk seite1.pdf seite2.pdf seite3.pdf cat output output.pdf

Split:pdftk full-pdf.pdf cat 12-15 output outfile_p12-15.pdf
you pass the filename of the main pdf, then you tell it to only include certain pages (12-15 in this example) and output it to a new file.

if not installed:sudo snap install pdftk

Also pdfjoin a.pdf b.pdf will create a new b-joined.pdf with the contents of a.pdf and b.pdf


pdfunite is fine to merge entire PDFs. If you want, for example, pages 2-7 from file1.pdf and pages 1,3,4 from file2.pdf, you have to use pdfseparate to split the files into separate PDFs for each page to give to pdfunite.

At that point you probably want a program with more options. qpdf is the best utility I've found for manipulating PDFs. pdftk is bigger and slower and Red Hat/Fedora don't package it because of its dependency on gcj. Other PDF utilities have Mono or Python dependencies. I found qpdf produced a much smaller output file than using pdfseparate and pdfunite to assemble pages into a 30-page output PDF, 970kB vs. 1,6450 kB. Because it offers many more options, qpdf's command line is not as simple; the original request to merge file1 and file2 can be performed with

qpdf --empty --pages file1.pdf file2.pdf -- merged.pdf


Use PDF tools from python https://pypi.python.org/pypi/pdftools/1.0.6

Download the tar.gz file and uncompress it and run the command like below

python pdftools-1.1.0/pdfmerge.py -o output.pdf -d file1.pdf file2.pdf file3 
You should install pyhton3 before you run the above command

This tools support the below

add
insert
Remove
Rotate
Split
Merge
Zip
You can find more details in the below link and it is open source

https://github.com/MrLeeh/pdftools

PdfCpu works great:

pdfcpu merge c.pdf a.pdf b.pdf
https://pdfcpu.io/core/merge