sldtoppm --version (return code: 0)
sldtoppm: Using libpbm from Netpbm Version: Netpbm 10.0
sldtoppm: BSD defined
sldtoppm: RGB_ENV='RGBDEF'
sldtoppm: RGBENV= 'RGBDEF' (env vbl is unset)
sldtoppm -h (return code: 1)
usage: sldtoppm [-verbose] [-info] [-adjust] [-scale <s>]
[-dir] [-lib|-Lib <name>]
[-xsize|-width <x>] [-ysize|-height <y>] [sldfile]