use strict;
use warnings;

my $a = "abcdabcd";
{
	my $b = join('.',unpack('CCCC',$a));
	print $b, "\n";
}
{
	my $b = join('.',unpack('CCCC',substr($a,0,4)));
	print $b, "\n";
}
{
	my $b = join('.',unpack('(CCCC)*',$a));
	print $b, "\n";
}
{
	my $b = join('.',unpack('(CCCC)*',substr($a,0,4)));
	print $b, "\n";
}

##</code><code>##

97.98.99.100
97.98.99.100
97.98.99.100.97.98.99.100
97.98.99.100