Win8 Strawberry 5.30.3.1 (64) Fri 01/29/2021 22:12:11 C:\@Work\Perl\monks >perl -Mstrict -Mwarnings use Regexp::Common; my $rx_extract_ipv4 = qr{ (? (%s) \n\n", join ' ', map "'$_'", @ips; } ^Z '1.2.3.4foo11.22.33.44bar111.222.233.244 0.0.0.0 .255.255.255.255.' -> ('1.2.3.4' '11.22.33.44' '111.222.233.244' '0.0.0.0' '255.255.255.255') '999.9.9.999 256.255.255.256' -> ()