pgmslice --version (return code: 0)
pgmslice: Using libpbm from Netpbm Version: Netpbm 10.0
pgmslice: BSD defined
pgmslice: RGB_ENV='RGBDEF'
pgmslice: RGBENV= 'RGBDEF' (env vbl is unset)
pgmslice -h (return code: 1)
usage: pgmslice -row|-col <line> [pgmfile]