I ported Ken Thompon’s shell from UNIX 6th edition in 30 minutes:
http://sswam.net/code/unix6

This has been done already at http://v6shell.org, and I’m sure they did a better job, but there was this long copyright notice…

I am making a Flow Based Programming system for the shell, http://sswam.net/code/net2sh. It is a self-hosted translator; there is also a tool to draw graphs from the programs, like these:

net2sh – convert FBP net programs into shell script

net2dot – convert FBP net programs into dot graphs