Shell Programming and Scripting

I would like to to catch the ip at the following line with egrep and regexp:
ip = 192.9.110.20

and I built the following regexp to do it:
(?<=ip\s=\s)\S+

when I check it with regexp simulator, it works but when I use it in the following egrep command it doesn't work -
egrep -e '(?<=ip\s=\s)\S+' config.ini

what I should do to make it work?!

I'm working with bash on rhel 3 and also tried on rhel 5

Thanks.

these metachar (\s,\S...etc) are not exist in egrep but they are in perl
so use the below perl code:-

Code:

perl -wnl -e  '/(\d+.?)+/ and print $& ; '

Cool.
Thanks a lot!