Printing two pages per sheet from the command line

There is the pdfnup (or pdfjam) command line tool. You can install it from the repositories of your distribution (sudo apt-get install pdfjam for Debian-based distributions, yaourt -S pdfnup on Arch etc).

The default options will take the input PDF file and produce an output PDF with two input pages per page:

pdfnup -o output.pdf input.pdf