Various tips and tricks that I have found Useful

How to print several logical pages on the same sheet of paper (in Un*x)

For text files use enscript package.
> enscript -r2 fileName
will print the text in two columns arranged side-by-side in the landscape mode. enscript has more useful options, for example -G would print a nice header on every page.

For postscript or PDF (at least on CUPS based printing systems) use
> lpr -o number-up=N
to print N document pages printed per page (2 will be automatically printed in the landscape mode). Add -o sides=two-sided-short-edge to flip on the short edge.