or download this
my $line = "00:04:23:a5:ce:6d > ff:ff:ff:ff:ff:ff, ethertype IPv6 (0x8
+6dd), length 66: ::.61701 > ff02::1:2:.547: [udp sum ok] dhcp solicit
+ (xid=493907) (len12, hlim 255)";
my @match = $line =~ /^(\S+) > (\S+),.*IPv6.*\.547:\.*xid=(\d+)/;
print "@match\n";