IP addresses in Perl

With Perl you can do many interesting transformations of IP-numbers. Below is two small examples allowing conversions from “IP quad” (xxx.xxx.xxx.xxx) format to a single decimal and back.

sub ip2dec ($) {
    return unpack N => pack CCCC => split /\\./ => shift;
}

sub dec2ip ($) {
    return join '.' => map { ($\_\[0\] >> 8\*(3-$\_)) % 256 } 0 .. 3;
}

In CPAN you can find many modules aimed at using and manipulating IP-addressees. Some include Net::IP and IP::Country.