I am working on a UNIX system and I'd like to merge thousands of PDF files into one file in order to print it. I don't know how many pages they are in advance.
I'd like to print it double sided, such that two files will not be on the same page.
Therefore it I'd the merging file to be aligned such that every file will begin in odd page and a blank page will be added if the next place to write is an even page.
Here's the solution I use (it's based on @Dingo's basic principle, but uses an easier approach for the PDF manipulation):
Create PDF file with a single blank page
First, create a PDF file with a single blank page somewhere (in my case, it is located at /path/to/blank.pdf). This command should work (from this thread):
touch blank.ps && ps2pdf blank.ps blank.pdf
Run Bash script
Then, from the directory that contains all my PDF files, I run a little script that appends the blank.pdf file to each PDF file with an odd page number:
#!/bin/bash
for f in *.pdf; do
let npages=$(pdfinfo "$f"|grep 'Pages:'|awk '{print $2}')
let modulo="($npages %2)"
if [ $modulo -eq 1 ]; then
pdftk "$f" "/path/to/blank.pdf" output "aligned_$f"
# or
# pdfunite "$f" "/path/to/blank.pdf" "aligned_$f"
else
cp "$f" "aligned_$f"
fi
done
Combine the results
Now, all aligned_-prefixed files have even page numbers, and I can join them using
pdftk aligned_*.pdf output result.pdf
# or
pdfunite aligned_*.pdf result.pdf
Tool info:
ps2pdf is in the ghostscript package in most Linux distrospdfinfo, pdfunite are from the Poppler PDF rendering library (usually the package name is poppler-utils or poppler_utils)pdftk is usually its own package, the pdftk package
your problem can be more easily solved if you look at this from an another point of view
to obtain that, in printing, page 1 of second pdf file will be not attached to last page of first pdf file on the same sheet of paper, and, more generally, first page of subsequent pdf file will be not printed on the back of the same sheet with the last page of the precedent pdf file
you need to perform a selective addition of one blank page only to pdf files having and odd number of pages
I wrote a simple script named abbblankifneeded that you can put in a file and then copy in /usr/bin or /usr/local/bin
and then invoke in folder where you have your pdf with this syntax
for f in *.pdf; do addblankifneeded $f; done
this script adds a blank page at end to pdf files having an odd number of pages, skipping pdf files having already an even number of pages and then join together all pdf into one
requirements: pdftk, pdfinfo
NOTE: depending from your bash environment, you may need to replace sh interpreter with bash interpreter in the first line of script
#!/bin/sh
#script to add automatically blank page at the end of a pdf documents, if count of their pages is a not a module of 2 and then to join all pdfs into one
#
# made by Dingo
#
# dokupuppylinux.co.cc
#
#http://pastebin.com/u/dingodog (my pastebin toolbox for pdf scripts)
#
filename=$1
altxlarg="`pdfinfo -box $filename| grep MediaBox | cut -d : -f2 | awk '{print $3 FS $4}'`"
echo "%PDF-1.4
%µí®û
3 0 obj
<<
/Length 0
>>
stream
endstream
endobj
4 0 obj
<<
/ProcSet [/PDF ]
/ExtGState <<
/GS1 1 0 R
>>
>>
endobj
5 0 obj
<<
/Type /Halftone
/HalftoneType 1
/HalftoneName (Default)
/Frequency 60
/Angle 45
/SpotFunction /Round
>>
endobj
1 0 obj
<<
/Type /ExtGState
/SA false
/OP false
/HT /Default
>>
endobj
2 0 obj
<<
/Type /Page
/Parent 7 0 R
/Resources 4 0 R
/Contents 3 0 R
>>
endobj
7 0 obj
<<
/Type /Pages
/Kids [2 0 R ]
/Count 1
/MediaBox [0 0 595 841]
>>
endobj
6 0 obj
<<
/Type /Catalog
/Pages 7 0 R
>>
endobj
8 0 obj
<<
/CreationDate (D:20110915222508)
/Producer (libgnomeprint Ver: 2.12.1)
>>
endobj
xref
0 9
0000000000 65535 f
0000000278 00000 n
0000000357 00000 n
0000000017 00000 n
0000000072 00000 n
0000000146 00000 n
0000000535 00000 n
0000000445 00000 n
0000000590 00000 n
trailer
<<
/Size 9
/Root 6 0 R
/Info 8 0 R
>>
startxref
688
%%EOF" | sed -e "s/595 841/$altxlarg/g">blank.pdf
pdftk blank.pdf output fixed.pdf
mv fixed.pdf blank.pdf
pages="`pdftk $filename dump_data | grep NumberOfPages | cut -d : -f2`"
if [ $(( $pages % 2 )) -eq 0 ]
then echo "$filename has already a multiple of 2 pages ($pages ). Script will be skipped for this file" >>report.txt
else
pdftk A=$filename B=blank.pdf cat A B output blankadded.pdf
mv blankadded.pdf $filename
pdffiles=`ls *.pdf | grep -v -e blank.pdf -e joinedtogether.pdf| xargs -n 1`; pdftk $pdffiles cat output joinedtogether.pdf
fi
exit 0
You can use PDFsam:
Disclaimer: I'm the author of the tools I'm mentioning here.
It's a free and open source command line interface for performing pdf manipulations such as merge or split. The merge command has an option stating:
[--addBlanks] : add a blank page after each merged document if the number of pages is odd (optional)
Since you just need to print the pdf I'm assuming you don't care about the order your documents are merged. This is the command you can use:
sejda-console merge -d /path/to/pdfs_to_merge -o /outputpath/merged_file.pdf --addBlanks
It can be downloaded from the official website sejda.org.
This is a web application backed by Sejda and has the same functionalities mentioned above but through a web interface. You are required to upload your files so, depending on the size of your input set, it might not be the right solution for you.
If you select the merge command and upload your pdf documents you will have to flag the checkbox Add blank page if odd page number to get the desired behaviour.
Here is a PowerShell version of the most popular solution using pdftk. I did this for windows but you can use PowerShell Core for other platforms.
# install pdftk server if on windows
# https://www.pdflabs.com/tools/pdftk-server/
$blank_pdf_path = ".\blank.pdf"
$input_folder = ".\input\"
$aligned_folder = ".\aligned\"
$final_output_path = ".\result.pdf"
foreach($file in (Get-ChildItem $input_folder -Filter *.pdf))
{
# easy but might break if pdfinfo output changes
# takes 7th line with the "Page: 2" and matches only numbers
(pdfinfo $file.FullName)[7] -match "(\d+)" | Out-Null
$npages = $Matches[1]
$modulo = $npages % 2
if($modulo -eq 1)
{
$output_path = Join-Path $aligned_folder $file.Name
pdftk $file.FullName $blank_pdf_path output $output_path
}
else
{
Copy-Item $file.FullName -Destination $aligned_folder
}
}
$aligned_pdfs = Join-Path $aligned_folder "*.pdf"
pdftk $aligned_pdfs output $final_output_path
pyPDF package./path/to/blank.pdf (I've created blank pdf pages here).pdfmerge.py in any directory of your $PATH. (I'm not a Windows user. This is straight forward under Linux. Please let me know if you get errors / if it works.)pdfmerge.py executableRun uniprint.py a directory that contains only PDF files you want to merge.
#!/usr/bin/env python
# -*- coding: utf-8 -*-
from argparse import ArgumentParser
from glob import glob
from pyPdf import PdfFileReader, PdfFileWriter
def merge(path, blank_filename, output_filename):
blank = PdfFileReader(file(blank_filename, "rb"))
output = PdfFileWriter()
for pdffile in glob('*.pdf'):
if pdffile == output_filename:
continue
print("Parse '%s'" % pdffile)
document = PdfFileReader(open(pdffile, 'rb'))
for i in range(document.getNumPages()):
output.addPage(document.getPage(i))
if document.getNumPages() % 2 == 1:
output.addPage(blank.getPage(0))
print("Add blank page to '%s' (had %i pages)" % (pdffile, document.getNumPages()))
print("Start writing '%s'" % output_filename)
output_stream = file(output_filename, "wb")
output.write(output_stream)
output_stream.close()
if __name__ == "__main__":
parser = ArgumentParser()
# Add more options if you like
parser.add_argument("-o", "--output", dest="output_filename", default="merged.pdf",
help="write merged PDF to FILE", metavar="FILE")
parser.add_argument("-b", "--blank", dest="blank_filename", default="blank.pdf",
help="path to blank PDF file", metavar="FILE")
parser.add_argument("-p", "--path", dest="path", default=".",
help="path of source PDF files")
args = parser.parse_args()
merge(args.path, args.blank_filename, args.output_filename)
Please make a comment if this works on Windows and Mac.
Please always leave a comment if it doesn't work / it could be improved.
It works on Linux. Joining 3 PDFs to a single 200-page PDF took less then a second.
Martin had a good start. I updated to PyPdf2 and made a few tweaks like sorting the output by filename.
#!/usr/bin/env python
# -*- coding: utf-8 -*-
from argparse import ArgumentParser
from glob import glob
from PyPDF2 import PdfFileReader, PdfFileWriter
import os.path
def merge(pdfpath, blank_filename, output_filename):
with open(blank_filename, "rb") as f:
blank = PdfFileReader(f)
output = PdfFileWriter()
filelist = sorted(glob(os.path.join(pdfpath,'*.pdf')))
for pdffile in filelist:
if pdffile == output_filename:
continue
print("Parse '%s'" % pdffile)
document = PdfFileReader(open(pdffile, 'rb'))
for i in range(document.getNumPages()):
output.addPage(document.getPage(i))
if document.getNumPages() % 2 == 1:
output.addPage(blank.getPage(0))
print("Add blank page to '%s' (had %i pages)" % (pdffile, document.getNumPages()))
print("Start writing '%s'" % output_filename)
with open(output_filename, "wb") as output_stream:
output.write(output_stream)
if __name__ == "__main__":
parser = ArgumentParser()
# Add more options if you like
parser.add_argument("-o", "--output", dest="output_filename", default="merged.pdf",
help="write merged PDF to FILE", metavar="FILE")
parser.add_argument("-b", "--blank", dest="blank_filename", default="blank.pdf",
help="path to blank PDF file", metavar="FILE")
parser.add_argument("-p", "--path", dest="path", default=".",
help="path of source PDF files")
args = parser.parse_args()
merge(args.path, args.blank_filename, args.output_filename)
`
The code by @Chris Lercher in https://stackoverflow.com/a/12761103/1369181 did not quite work for me. I do not know whether that is because I am working on Cygwin/mintty. Also, I have to use qpdf instead of pdftk. Here is the code that has worked for me:
#!/bin/bash
for f in *.pdf; do
npages=$(pdfinfo "$f"|grep 'Pages:'|sed 's/[^0-9]*//g')
modulo=$(($npages %2))
if [ $modulo -eq 1 ]; then
qpdf --empty --pages "$f" "path/to/blank.pdf" -- "aligned_$f"
else
cp "$f" "aligned_$f"
fi
done
Now, all "aligned_" files have even page numbers, and I can join them using qpdf (thanks to https://stackoverflow.com/a/51080927):
qpdf --verbose --empty --pages aligned_* -- all.pdf
And here the useful code from https://unix.stackexchange.com/a/272878 that I have used for creating the blank page:
echo "" | ps2pdf -sPAPERSIZE=a4 - blank.pdf
This one worked for me. Have used pdfcpu on macos. Can be installed this way:
brew install pdfcpu
And have slightly adjusted the code from https://stackoverflow.com/a/12761103/1369181
#!/bin/bash
mkdir aligned
for f in *.pdf; do
let npages=$(pdfcpu info "$f"|grep 'Page count:'|awk '{print $3}')
let modulo="($npages %2)"
if [ $modulo -eq 1 ]; then
pdfcpu page insert -pages l -mode after "$f" "aligned/$f"
else
cp "$f" "aligned/$f"
fi
done
pdfcpu merge merged-aligned.pdf aligned/*.pdf
rm -rf aligned
NB! It creates and removes "aligned" directory in the current directory. So feel free to improve it to make it safe for use.
