debootstrap is a tool which will install a Debian base system into
a subdirectory of another, already installed system. It doesn't require
an installation CD, just access to a Debian repository.

In FreeBSD, you can use debootstrap to install Debian into a subdirectory
of your existing FreeBSD installation and then run Debian Linux in a jail
or chroot.

WWW: https://wiki.debian.org/Debootstrap
