pdfbmshift

#! /usr/local/bin/python3
import argparse
import tempfile
import shutil
import subprocess


def shiftBookMarks(n, input_file, output_file, begin, end):
    if not output_file:
        output_file = input_file

    if n != 0:
        with tempfile.NamedTemporaryFile(mode='w+t') as in_bmarks, tempfile.NamedTemporaryFile(mode='w+t') as out_bmarks:
            subprocess.run('pdftk %s dump_data_utf8 output %s' % (input_file, in_bmarks.name), shell=True)

            for line in in_bmarks:
                if line.startswith('BookmarkPageNumber:'):
                    parts = line.split(' ')

                    if begin <= int(parts[1]) <= end:
                        out_bmarks.write(parts[0] +' '+ str(int(parts[1])+n)+'\n')
                    else:
                        out_bmarks.write(line)
                else:
                    out_bmarks.write(line)
            out_bmarks.flush()
            update_bmarks = subprocess.run('pdftk %s update_info %s output %s'%(input_file, out_bmarks.name, output_file), shell=True)

            return update_bmarks.returncode

    elif n == 0 and output_file == input_file:
        return 0

    else:
        shutil.copy(input_file, output_file)
        return 0

parser = argparse.ArgumentParser(description = 'Will shift the bookmarks of a pdf a given number of pages forward or backward. Requires pdftk.')
parser.add_argument('input', help='A pdf file with bookmarks.')
parser.add_argument('output', help = 'Output filename cannot match input fileneame.')
parser.add_argument('shift', help = 'The number of pages to shift the bookmarks, use negitive page numbers to shift backwards.',type=int)
parser.add_argument('--begin','-b', default = 0, type = int, help = 'Page to begin shifting bookmarks.')
parser.add_argument('--end', '-e', default = 100000, type = int, help = 'Page to stop shifting bookmarks.')
args = parser.parse_args()

if args.input:
    shiftBookMarks(args.shift, args.input, args.output, args.begin, args.end)