>>8
It's not purely scheme but a scheme like language pushed by gnu. You can find it in a lot of gnu tools.
The problem with calling it scheme like is how gnu is usually known as the opposite of simplicity but I haven't used guile enough to see if it has that many extensions compared to s7. I know it's userland utilities do compared to bsd and svr ones, tons of tools have more usage overlap and it's even more complicated.