CUPS printing of PDF files

Question

How can I tell the lpr command (CUPS) that my file is actually a PDF?

lpr file.pdf

won't print anything.

Answer 1

Is this really the CUPS-based lpr, or is it a remnant of another spooling system which was not removed before installing CUPS?

Check it by running ldd $(which lpr) and see if there is any reference to libcups.

Also, the complete command should be:

lpr -P printername file.pdf

For a correctly and completely installed CUPS you'd not need to tell it the file type you send to print. It will "auto-type" the input, and apply the right conversion filters to make it digestable by the target printer.