mdsh is a bash script compiler and interpreter for markdown files. It can be used in a #! line to make markdown files executable, or it can be used as a standalone tool to generate dependency-free, distributable bash scripts from markdown files.
By default, mdsh only considers shell code blocks to be bash code, but you can also use @mdsh blocks to define handlers for other languages. For example, this script will run python-tagged code blocks by piping them to the python command: