I need to merge a few dozed pdfs, and i want all of the input pdfs to start on an odd page in the output pdf.
Example: A.pdf has 3 pages, B.pdf has 4 pages. I don't want my output to have 7 pages. What I want is an 8-page pdf in which pages 1-3 are from A.pdf, page 4 is empty, and pages 5-8 are from B.pdf. How can I do this?
I know about pdftk, but I didn't find such an option in the man page.
The pypdf library makes this sort of things easy if you're willing to write a bit of Python. Save the code below in a script called pdf-cat-even (or whatever you like), make it executable (chmod +x pdf-cat-even), and run it with output redirected to a file ./pdf-cat-even a.pdf b.pdf >concatenated.pdf — current versions of pypdf don't support writing to a pipe).
#!/usr/bin/env python3 import copy, sys from pypdf import PdfWriter, PdfReader output = PdfWriter() output_page_number = 0 alignment = 2 # to align on even pages for filename in sys.argv[1:]: # This code is executed for every file in turn input = PdfReader(filename) for p in input.pages: # This code is executed for every input page in turn output.add_page(p) output_page_number += 1 while output_page_number % alignment != 0: output.add_blank_page() output_page_number += 1 output.write(sys.stdout.buffer) 
./pdf-cat-even $(cat list-of-file-names.txt) >concatenated.pdf <list-of-file-names.txt tr '\n' '\0' | xargs -0 ./pdf-cat-even >concatenated.pdf The first step is to produce a pdf file with an empty page. You can do this easily with a lot of programs (LibreOffice/OpenOffice, inkscape, (La)TeX, scribus, etc.)
Then just include this empty page where needed:
pdftk A.pdf empty_page.pdf B.pdf output result.pdf If you want to do this automatically with a script, you can use e.g. pdftk file.pdf dump_data | grep NumberOfPages | egrep -o '[0-9]*' to extract the page count.
pdftk --version returns pdftk 1.44. I remember that my more-bash-savvy friends spent at least 15 minutes trying different things to get this work and gave up. Gilles' answer worked for me, but since i have to merge many files it's more convenient if i can read their names from a text file. I've slightly modified Gilles' code to do just that, maybe it would help someone else:
#!/usr/bin/env python # requires PyPdf library, version 1.13 or above - # its homepage is http://pybrary.net/pyPdf/ # running: ./this-script-name file-with-pdf-list > output.pdf import copy, sys from pyPdf import PdfFileWriter, PdfFileReader output = PdfFileWriter() output_page_number = 0 # every new file should start on (n*alignment + 1)th page # (with value 2 this means starting always on an odd page) alignment = 2 listoffiles = open(sys.argv[1]).read().splitlines() for filename in listoffiles: # This code is executed for every file in turn input = PdfFileReader(open(filename)) for p in [input.getPage(i) for i in range(0,input.getNumPages())]: # This code is executed for every input page in turn output.addPage(p) output_page_number += 1 while output_page_number % alignment != 0: output.addBlankPage() output_page_number += 1 output.write(sys.stdout) You could also use LaTeX to do this (though I'm aware it's probably not what you want). Something like the following should work:
\documentclass{book} \usepackage{pdfpages} \begin{document} \includepdf[pages=-]{A} \cleardoublepage % Make sure we clear to an odd page \includepdf[pages=-]{B} % This inserts all pages. Or you can specify specific pages, a range, or `{}` for a blank page \end{document} Note that \cleardoublepage only inserts a blank page with classes that are made for two sided printing (eg. book)
More options and info on pdfpages can be found on CTAN.
\includepdf[pages=-]{...}. \cleardoublepage only inserts a blank page if you're using a class made for two sided printing. I was using article which doesn't work; I fixed it and updated the question to reflect that. \includepdf includes only the first page by default (not all pages). \documentclass[twoside]{article} works also. Here's the code with PyPDF2 and python3
#!/usr/bin/env python # requires PyPdf2 library, version 1.26 or above - # its homepage is https://pythonhosted.org/PyPDF2/index.html # running: ./this-script-name output.pdf file-with-pdf-list import copy, sys from PyPDF2 import PdfFileWriter, PdfFileReader output = PdfFileWriter() output_page_number = 0 # every new file should start on (n*alignment + 1)th page # (with value 2 this means starting always on an odd page) alignment = 2 for filename in sys.argv[2:]: # This code is executed for every file in turn input = PdfFileReader(open(filename, "rb")) output.appendPagesFromReader(input) output_page_number += input.getNumPages() while output_page_number % alignment != 0: output.addBlankPage() output_page_number += 1 output.write(open(sys.argv[1], "wb")) 