hmac256 --version (return code: 0)
hmac256 (Libgcrypt) 1.7.6-beta Copyright (C) 2008 Free Software Foundation, Inc. License LGPLv2.1+: GNU LGPL version 2.1 or later <http://gnu.org/licenses/old-licenses/lgpl-2.1.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.
hmac256 (return code: 1)
usage: hmac256 [--binary] [--stdkey] key [filename]