I must not be a true perl master, because I hacked on your program and it got BIGGER!

#!/usr/bin/perl

# you have to use strict and warnings unless you
# have a really good reason not to.
use strict;
use warnings;

my $string = "il asdfasdfasdf";
my $tag = "";

# use matching here instead of substitution
# all of the string should appear in the output
# also, don't need square brackets in match
if ($string =~ m/(\S{2})/)
{
    $tag = "<$1>";
}

# you don't need to concatenate, just interpolate the lot
$string = "$tag $string $tag";
print "string = $string\n";

__END__
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