example 1:
$a = "test test test";
$fmt = "A4 x1 A4 x1 A4 x1 A4";
@a = unpack($fmt, $a);
print join ("*",@a);
^D
x outside of string at - line 3.

example 2:
$a = "test test test ";
$fmt = "A4 x1 A4 x1 A4 x1 A4";
@a = unpack($fmt, $a);
print join ("*",@a);
^D
test*test*test*