 An example set of service definition directories.

 It is a real life example, used for the configuration of
a router with 4 ethernet interfaces and 2 wifi ones, behind
two ISPs (one fiber, one DSL), running a few services such
as a DNS cache and a web server for a local network.
 All the scripts are genuine, only specific values such as
IP addresses are not present (machine-specific data is stored
in /etc, not in the s6-rc source directories).
 The scripts use standard POSIX tools, the whole suite of
skarnet.org tools, and some specialized Linux tools such as
iproute2, iw, etc.

 ok-all is the entry point, the "top" bundle containing all
the services used for normal operation of the machine.
The stage 2 init script of this machine is basically
"s6-rc-init && s6-rc change ok-all".

 Don't look too much into the weird ipv6 stuff, this is mostly
a bunch of workarounds for a very broken ISP-provided device.
