pnmtosgi --version (return code: 0)
pnmtosgi: Using libpbm from Netpbm Version: Netpbm 10.0
pnmtosgi: BSD defined
pnmtosgi: RGB_ENV='RGBDEF'
pnmtosgi: RGBENV= 'RGBDEF' (env vbl is unset)
pnmtosgi -h (return code: 1)
usage: pnmtosgi [-verbatim|-rle] [-imagename <name>] [pnmfile]