There are some other ways to slice and compose PDFs under Linux. The pdfpages package for LaTeX is pretty handy, but it's a bit awkward if you don't need LaTeX

There are some other ways to slice and compose PDFs under Linux. The pdfpages package for LaTeX is pretty handy, but it's a bit awkward if you don't need LaTeX. Then there's PyPDF2. Although I don't think it fully supports Python3, it works fine under Python2 and has been quite useful for me.