sed command extensions

[root@b ~]# cat f.txt
inet addr:192.168.0.110 Bcast:192.168.0.255 Mask:255.255.255.0
[root@b ~]# cat f.txt | sed -nr 's/^.*inet addr:(.*) Bcast:.*$/ip:\1/gp'
ip:192.168.0.110
[root@b ~]# cat f.txt | sed -nr 's/^.*inet addr:(.*) Bcast:(.*) Mask:.*$/ip:\1\nBcast:\2/gp'
ip:192.168.0.110
Bcast:192.168.0.255