pdfcrop --margins '-4 -4 -4 -5' --clip input.pdf output.pdf
calibre is a powerful and easy to use e-book manager. Users say it’s outstanding and a must-have. It’ll allow you to do nearly everything and it takes things a step beyond normal e-book software. It’s also completely free and open source and great for both casual users and computer experts.
PDFCrop is a Perl script that crops the white margins of PDF pages and rescales them to fit a standard size sheet of paper. It makes the printed pages far more attractive to read!