'Grep'ing the IP out of a finger command on linux

Question

I am using ssh to access another machine and require the IP from which I am sshing from. Finger gives this, but I don't know how to isolate this from the information given. So far I have:

finger | grep $USER

Which produces:

jonno     Jonathan Mackenzie   pts/9          Sep 21 16:23 (111.111.111.111)

What is the last grep required to isolate the IP address (i changed it here for security reasons)?

Answer 1

Quick and dirty:

finger | grep $USER | egrep -o "[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}"

Answer 2

When you ssh somewhere a few environment variables are set:

SSH_CLIENT 
SSH_TTY  
SSH_CONNECTION

do take a look at them, they are quite useful.