pdfxup
N-up PDF pages.
TLDR
Create a 2-up PDF
$ pdfxup -o [path/to/output.pdf] [path/to/input.pdf]
Create a PDF with 3 columns and 2 lines per page
$ pdfxup -x [3] -y [2] -o [path/to/output.pdf] [path/to/input.pdf]
Create a PDF in booklet mode (2-up, and pages are sorted to form a book when folded)
$ pdfxup -b -o [path/to/output.pdf] [path/to/input.pdf]
