fitstopnm --version (return code: 0)
fitstopnm: Using libpbm from Netpbm Version: Netpbm 10.0
fitstopnm: BSD defined
fitstopnm: RGB_ENV='RGBDEF'
fitstopnm: RGBENV= 'RGBDEF' (env vbl is unset)
fitstopnm -h (return code: 1)
usage: fitstopnm [-image N] [-noraw] [-scanmax] [-printmax] [-min f] [-max f] [FITSfile]