I want to merge several hundred pdf files in a directory automatically according to their file names.
The files 1000.1.pdf 1000.2.pdf 1000.3.pdf 1000.x.pdf should be merged into 1000.pdf
2000.abc.pdf 2000.def.pdf 2000.ghi.pdf 2000.jkl.pdf 2000.5.pdf into 2000.pdf.
I don’t want to use solutions based on Preview/Automator (if available) because compared to third party software like Adobe Acrobat or PDFpen merging pdf files often (depending on the source documents) results in a significant increase in file size (see e.g. What causes PDF file size to increase when saving in Preview?)
Do you have any recommendations? Thank you!