in reply to String eval is cool

Just in case you want to save some more bytes ;-)

usage: cidr.pl 195.233.48.24/27 

#!/usr/bin/perl
$m=pack B32,pop=~'/'x$';printf"$` network %vd broadcast %vd netmask %v
+d\n",($z=eval$`)&$m,$z|~$m,$m

[download]

cheers,
--shmem 

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

In Section Cool Uses for Perl