192.168.1.50 192.168.6.50 192.168.8.50 #### use warnings; use strict; while (){ print "$_\n" if /192\.168\.[1-99]\.\d+/g; } __DATA__ 192.168.1.50 192.168.6.50 192.168.8.50 192.168.28.50 192.168.58.50 192.168.101.50 192.168.201.50