Re: Detect whether attached or detached from screen session?

[Peder Stray]

On Tue, 14 Oct 2008, Trent W. Buck wrote:

> "Sven Hazejager"
> <address@hidden> writes:
>
> > I'm using screen to keep some applications open over a remote SSH
> > connection that sometimes is killed. What I would like to do, is to
> > somehow find out whether I am logged in (attached) or disconnected
> > from the screen session.
> >
> > Reason is that I want procmail to send incoming mail to my BlackBerry
> > if I'm disconnected, but NOT do that when I'm SSH-ing into my Pine
> > session.
>
> I don't know how to achieve that, but perhaps there's a different 
> approach to the problem -- such as always forwarding all mail to an IMAP 
> server that you can access from both the blackberry and from pine.

The screen-socket has execute permissions when attached, and none when 
detached, like this:

attached:

ls -l /tmp/uscreens/S-peder/4598.irc
prwx------ 1 peder peder 0 Oct 14 00:00 /tmp/uscreens/S-peder/4598.irc

detached:
ls -l /tmp/uscreens/S-peder/4598.irc
prw------- 1 peder peder 0 Oct 14 07:06 /tmp/uscreens/S-peder/4598.irc

Guess you can test for that i procmail by something like:

:0c
*? perl -e 'exit ! grep { (stat $_)[2] & 0100 } </tmp/uscreens/S-peder/*>'
address@hidden

--
  Peder Stray