pgmkernel --version (return code: 0)
pgmkernel: Using libpbm from Netpbm Version: Netpbm 10.0
pgmkernel: BSD defined
pgmkernel: RGB_ENV='RGBDEF'
pgmkernel: RGBENV= 'RGBDEF' (env vbl is unset)
pgmkernel -h (return code: 1)
usage: pgmkernel [-weight f] width [height]