Rearranges pages for book-like fold-able printouts.

Pages

#!/usr/bin/env python

"""
This script calculates and returns a string of page numbers for
printing book-like fold-able printouts.

Use it like:
    python pages.py 42 > pages.file
    pdftk input.pdf cat `cat pages.file` output output.pdf

NOTE: Only first parameter is recognized when executed.

Thanks to http://ubuntuforums.org/showthread.php?t=868950 for the
inspiration.
"""

from sys import argv

def pages(num, topfirst=True, seperator=" "):
    """
    num       = number of pages
    topfirst  = whether you like to print with or without turning the sheet
                on each printed front (Default: True)
    seperator = string between the page numbers (Default: ' ')

    It basically continues (4,1,2,3,...) which are the four sides of one
    printout and adds remaining pages.
    """
    order = (4, 1, 2, 3,)
    a = ""
    b = ""
    c = ""
    for i in range(num/4):
        a += str(order[0]+4*i)+seperator
        a += str(order[1]+4*i)+seperator
        b += str(order[2]+4*i)+seperator
        b += str(order[3]+4*i)+seperator
        for o in order:
            c += str(o+4*i)+seperator
    for i in range(num%4):
        b += str(num-num%4+i)+seperator
        c += str(num-num%4+i)+seperator
    if topfirst:
        return a+b
    else:
        return c

if __name__ == "__main__":
    if len(argv):
        print pages(int(argv[1]))