[BusyBox] Syntax of files used by ifup

[Holger Schurig]

> But where to put the IP adress and netmask? And what is the format of
> this file?

http://misc.eecs.umich.edu/cgi-bin/man2html?interfaces+5
http://misc.eecs.umich.edu/cgi-bin/man2html?ifup+8