Add margin to PDF file when merging using PDFTK or similar

Question

I have a large collection of half-page sized PDF cut-sheets that are held in a folder on my Linux server. A user to the site will want to create a booklet from a subset<

Answer 1

If you are still interested in this, you should have a look at pdfjam which allows you to offset and clip pdfs. With respect to your particular question you might do something like

pdfjam --twoside --offset '2cm 0cm' file.pdf

This shifts the even pages 2cm to the right and the odd one to the left.
pdfjam is a front end to the pdfpages package of pdflatex.