ppmdist --version (return code: 0)
ppmdist: Using libpbm from Netpbm Version: Netpbm 10.0
ppmdist: BSD defined
ppmdist: RGB_ENV='RGBDEF'
ppmdist: RGBENV= 'RGBDEF' (env vbl is unset)
ppmdist -h (return code: 1)
usage: ppmdist [-frequency|-intensity] [ppmfile]