pnmscale --version (return code: 0)
pnmscale: Using libpbm from Netpbm Version: Netpbm 10.0
pnmscale: BSD defined
pnmscale: RGB_ENV='RGBDEF'
pnmscale: RGBENV= 'RGBDEF' (env vbl is unset)
pnmscale -HELP (return code: 1)
pnmscale: With no dimension options, you must supply at least one parameter:
the scale factor.