redcarpet --version (return code: 0)
Redcarpet 3.3.3
redcarpet --help (return code: 0)
Usage: redcarpet [--parse <extension>...] [--render <extension>...] [--smarty] <file>...
--parse EXTENSION Enable a parsing extension
--render EXTENSION Enable a rendering extension
--smarty Enable Smarty Pants
-v, --version Display the current version
-h, --help Display this help message