null device in linux jail root

[Charles Howse]

Hi,

I installed Linux compatibility when I installed FBSD 4.8, but I've never 
really done anything with it.

While portupgrading , I was presented with a prompt that I don't know how to 
respond to:

You need to create the null device in your jail root environment.
Run the following commands outside the jail root environment,
and then press enter:
mkdir -m 0755 -p <Jail Root dir>/dev
rm -f <Jail Root dir>//compat/linux/dev/null
mknod <Jail Root dir>//compat/linux/dev/null c 2 2
chmod 666 <Jail Root dir>//compat/linux/dev/null

I found that this prompt comes from the makefile in the linux-base port, which 
I don't have access to at the moment, so I can't quote it exactly.

Clueless, I just pressed enter at the prompt, thinking I could always go back 
and do it later, or deinstall the port and reinstall it when I learn what to 
do.  

I know what a jail is, but how do I know what my <Jail Root dir> is?
Also, why the double slashes in the last 3 lines?  What do they mean?

What is the proper way to deal with this prompt?

-- 
Thanks,
Charles