Script knowing if in screen / screen window correponding to tty

[Buddy Burden]

Guys,

Been using screen for many years now and find it indispensible.  I have 
two minor questions (let me know if you think I should have broken this 
up into two separate posts).

1) Is there a way for a script to tell whether it's running inside 
screen?  I have a script that really should be run inside screen.  I 
don't want to just fire up a screen automatically, because the person 
might already be running it.  But the person forgets a lot too, so it 
would be nice to be able to flash a reminder to them, e.g. "Not running 
inside screen; continue anyway?".  Is this possible?

2) Is there any way to know what screen window corresponds to a given 
tty?  I generally have so many screen windows open that it's easy for me 
to lose track of what's where.  I often find that when I vi a file, it 
tells me I'm already vi'ing it somewhere else.  It gives me a pid, and 
from that I can get a tty, but I don't know where to go from there. 
(I'm not necessarily looking for an automated solution to this one.)  If 
this _is_ possible, then I further wonder if there's a way to get the 
tty printed on the windowlist--that would be particularly nifty.

TIA for any help.


                -- Buddy