while (<INPUt>) 
{ 
  push @array, $_;
}

##</code><code>##

while (<INPUT>)
{
   if (/$pattern/) # matches work by default on $_
   {
       do something with $_;
   }
}

##</code><code>##

$inner = "([0-5][0-9]|[0-9][1-8])";
$outer = "$inner.$inner.$inner/[0-6]"; # Can also be written $outer = join('.', $inner x 3) . "[0-6]"