prokshy is a small and lightweight script that uses unixexec to
exchange data through the special character file (/dev/vtcon/prokshy)
created by virtio_console(4). This script is designed to "standardize"
the way a command is executed from the host into the virtual machine.
The host connects to the unix(4) socket created by bhyve(8) and
then sends a command, a space, and then the data (or the command’s
argument). prokshy doesn’t care about the argument format: you can
use netstring, JSON, base64, or any other format that can be sent
for the command you’ve created. That’s the other advantage of
prokshy: it allows you to implement a "command," making it truly
flexible.