http://www.perlmonks.org?node_id=994396


in reply to replacing the last portions of an octet

An example using the IP decimal octet regex from Regexp::Common's friend Regexp::Common::net: 

>perl -wMstrict -le
"use Regexp::Common qw(net);
 ;;
 my $s = shift;
 print qq{'$s'};
 ;;
 $s =~ s{ \b ($RE{net}{IPv4}) - ($RE{net}{IPv4}) \b }
        { add_oct($1, -1) . '-' . add_oct($2, +1)   }xmse;
 print qq{'$s'};
 ;;
 sub add_oct {
   (my $ip = $_[0]) =~ s{ (\d+) \z }{ ($1 + $_[1]) & 0xff }xmse;
   return $ip;
   }
"  "192.168.1.1-192.168.1.255"
'192.168.1.1-192.168.1.255'
'192.168.1.0-192.168.1.0'

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