pnmcolormap --version (return code: 0)
pnmcolormap: Using libpbm from Netpbm Version: Netpbm 10.0
pnmcolormap: BSD defined
pnmcolormap: RGB_ENV='RGBDEF'
pnmcolormap: RGBENV= 'RGBDEF' (env vbl is unset)
pnmcolormap -HELP (return code: 1)
pnmcolormap: You must specify the number of colors in the output as an argument.