(\w+.+)

##</code><code>##

ip 10.1.1.1 goes with host name HOSTNAME-1A_1ST
ip 10.1.1.2 goes with host name HOSTNAME-1B_2ND
ip 10.3.1.1 goes with host name HOSTNAME-2A_1ST
ip 10.3.1.2 goes with host name HOSTNAME-2B_2ND