shkeleton looks pretty neat too! Amazing that it's 100% bash, as someone who shies away from bash scripting for all but the simplest scripts I can't imagine recreating argparse in it :)

Well, my definition of "embeddable" is a very loose one. All you really need to be able to do is allow the user to specify in/out/err streams, so that they could be anything: a log file, a socket, a Python function, etc. So maybe keep a var for each of these and redirect the echos to them?