psidtopgm --version (return code: 0)
psidtopgm: Using libpbm from Netpbm Version: Netpbm 10.0
psidtopgm: BSD defined
psidtopgm: RGB_ENV='RGBDEF'
psidtopgm: RGBENV= 'RGBDEF' (env vbl is unset)
psidtopgm -h (return code: 1)
usage: psidtopgm <width> <height> <bits/sample> [imagedata]