#!/bin/sh
# 1. Split the PDF into odd and even page files:
pdftk $1 cat odd output odd-$1 && pdftk $1 cat even output even-$1

# 2. Adjust margins for odd and even pages:
./pdfcrop1 -t '40 50 0 100' odd-$1 new-odd-$1
./pdfcrop1 -t '0 50 40 100'  even-$1 new-even-$1

# 3. Merge the pages back together:
pdftk O=new-odd-$1 E=new-even-$1 shuffle O E output new-$1