ppmtoacad --version (return code: 0)
ppmtoacad: Using libpbm from Netpbm Version: Netpbm 10.0
ppmtoacad: BSD defined
ppmtoacad: RGB_ENV='RGBDEF'
ppmtoacad: RGBENV= 'RGBDEF' (env vbl is unset)
ppmtoacad -h (return code: 1)
usage: ppmtoacad [-poly] [-dxb] [-white] [-background <col>]
[-aspect <f>] [-8] [ppmfile]