For now, oily-gentoo defines a minimal and automated path to replace /bin/bash and /bin/sh with oilshell in a stage 3 Gentoo tarball.
# Removes everything
./build clean
# Generate a rootfs
./build rootfs
# Enter a chroot
./build chroot
# Load the profile to have $PATH set, etc.
> . /etc/profile
# Remove mountpoints when finished
./build remove_mountsIdea and most code stolen from https://github.com/JoshMcguigan/cascade