pdf files cannot be sent directly to the printer. As with compressed and photo image files, sending a pdf file directly to the printer will cause it to jam or otherwise waste paper and not print correctly. Instead open the file using Adobe Acrobat Reader (or other software capable of opening an Adobe Acrobat file) and print the file from within that. In UNIX, some commands for this are: acroread, evince, okular, and xpdf.