pnmtofits --version (return code: 0)
pnmtofits: Using libpbm from Netpbm Version: Netpbm 10.0
pnmtofits: BSD defined
pnmtofits: RGB_ENV='RGBDEF'
pnmtofits: RGBENV= 'RGBDEF' (env vbl is unset)
pnmtofits -h (return code: 1)
usage: pnmtofits [-max f] [-min f] [pnmfile]