Allow the magic output filename `-`, which means send output to stdout instead of to a file.
Allow the magic output filename `-`, which means send output to
stdout instead of to a file.

gm2bv/discount,davidfstr/discount,gm2bv/discount,davidfstr/discount,gm2bv/discount,davidfstr/discount,binki/discount,binki/discount,binki/discount,binki/discount,binki/discount,gm2bv/discount,davidfstr/discount