ppmmake --version (return code: 0)
ppmmake: Using libpbm from Netpbm Version: Netpbm 10.0
ppmmake: BSD defined
ppmmake: RGB_ENV='RGBDEF'
ppmmake: RGBENV= 'RGBDEF' (env vbl is unset)
ppmmake (return code: 1)
usage: ppmmake <color> <width> <height>