Linux LPR print command

http://www.cups.org/documentation.php/options.html
Printing On Both Sides of the Paper

The -o sides=two-sided-short-edge and -o sides=two-sided-long-edge options will enable two-sided printing on the printer if the printer supports it. The -o sides=two-sided-short-edge option is suitable for landscape pages, while the -o sides=two-sided-long-edge option is suitable for portrait pages:

lp -o sides=two-sided-short-edge filename
lp -o sides=two-sided-long-edge filename
lpr -o sides=two-sided-long-edge filename

lpr -P MP560LAN -o InputSlot=Auto -o Resolution=600dpi -o PageSize=Letter