Crop 4x6" shipping labels out of Amazon FBA PDFs

cropamz.py

#!/usr/bin/python
# cropamz.py
# by Dan Nunn
# 2016-08-20

from pyPdf import PdfFileWriter, PdfFileReader
import sys
import os.path

# Default the filename to the first argument, otherwise use package.pdf
filename = "package.pdf" if len(sys.argv) < 2 or sys.argv[1] is None else sys.argv[1]
if filename[-4:] != ".pdf":
    filename += ".pdf"

# Make sure that the input file exists
if os.path.isfile(filename) is False:
    print "'" + filename + "' does not exist\n\n\tUsage: crop.py [filename.pdf]\n" + \
        "\tIf filename is not specified, defaults to package.pdf."
    exit(0)

input = PdfFileReader(file(filename, "rb"))
output = PdfFileWriter()

numPages = input.getNumPages()

for i in range(numPages):
    page = input.getPage(i)
    page.cropBox.lowerLeft = (30, 64)
    page.cropBox.upperRight = (487, 368)
    page.rotateClockwise(90)
    
    output.addPage(page)

outputStream = file("out.pdf", "wb")
output.write(outputStream)
outputStream.close()