ppmforge --version (return code: 0)
ppmforge: Using libpbm from Netpbm Version: Netpbm 10.0
ppmforge: BSD defined
ppmforge: RGB_ENV='RGBDEF'
ppmforge: RGBENV= 'RGBDEF' (env vbl is unset)
ppmforge -h (return code: 1)
usage: ppmforge
[-width|-xsize <x>] [-height|-ysize <y>] [-mesh <n>]
[-clouds] [-dimension <f>] [-power <f>] [-seed <n>]
[-hour <f>] [-inclination|-tilt <f>] [-ice <f>] [-glaciers <f>]
[-night] [-stars <n>] [-saturation <n>]