PPM2BBC

Usage:-
  ppm2bbc [<opts>]<ppm-file> [ [<opts>]<ppm-file>... ]
<opts> are -0,-1,-2,-4,-5 to set BBC MODE. -2 is default.
-a2,-a0 for aspect-correction, -hX1,-hsXa2 for halftoning:-
	X=0 for no halftoning,
	X=1 for fine halftoning (default),
	X=2 for coarse halftoning,
	X=3 for spiral halftoning,
	X=4 for diagonal halftoning.
	's' between the -h and the X value staggers the RGB values.
	Staggering often works well for MODE 2, but not for 2-colour modes.

Leave no spaces between the options and the filename.
eg. ppm2bbc -a2house.ppm -hs4a0picture.ppm

Tip: Use GNU bash if you want to use wildcards with this program...