Note: help and version output are generated by a naïve script which tries a few variants of
<command> --help, <command> -h etc. to find the command's help and version info.
Sometimes it gets lucky, sometimes it doesn't; if the output below looks wrong, it probably is.
st4topgm --version (return code: 0)
st4topgm: Using libpbm from Netpbm Version: Netpbm 10.0
st4topgm: BSD defined
st4topgm: RGB_ENV='RGBDEF'
st4topgm: RGBENV= 'RGBDEF' (env vbl is unset)
st4topgm -HELP (return code: None)