Thanks for this info. you are saying processes will terminate if trying to
write to stdout, but would otherwise stay alive if signals were set to be
ignored, correct?


> 
> An example of this that I use is a backgrounded ssh port forward:  "ssh -L 
> 1234:target.host:22 -N pivot.host &"
> I've had these last though complete logouts, which I like, until I really 
> want it to terminate and need to run netstat -lnp to find it again.
> 

The last part, about finding them and terminating them, you are looking for the
PID that is attached to the socket. I think for your purpose this would work
best: 'ps axu | grep ssh | grep 1234'

But I see your point.

As a side note, I have not had much luck with non-executing ssh tunnels (-N)
staying alive in most cases. I should also say, I am mostly using reverse
tunnels (-R).