use re 'debug';
my $str = "abc";
$str =~ m/.|$/g for 1..5;

__END__

Compiling REx ".|$"
Final program:
   1: BRANCH (3)
   2:   REG_ANY (5)
   3: BRANCH (FAIL)
   4:   SEOL (5)
   5: END (0)
minlen 0 
Matching REx ".|$" against "abc"
   0 <> <abc>                |   0| 1:BRANCH(3)
   0 <> <abc>                |   1|  2:REG_ANY(5)
   1 <a> <bc>                |   1|  5:END(0)
Match successful!
Matching REx ".|$" against "bc"
   1 <a> <bc>                |   0| 1:BRANCH(3)
   1 <a> <bc>                |   1|  2:REG_ANY(5)
   2 <ab> <c>                |   1|  5:END(0)
Match successful!
Matching REx ".|$" against "c"
   2 <ab> <c>                |   0| 1:BRANCH(3)
   2 <ab> <c>                |   1|  2:REG_ANY(5)
   3 <abc> <>                |   1|  5:END(0)
Match successful!
Matching REx ".|$" against ""
   3 <abc> <>                |   0| 1:BRANCH(3)
   3 <abc> <>                |   1|  2:REG_ANY(5)
                             |   1|  failed...
   3 <abc> <>                |   0| 3:BRANCH(5)
   3 <abc> <>                |   1|  4:SEOL(5)
   3 <abc> <>                |   1|  5:END(0)
Match successful!
Matching REx ".|$" against ""
   3 <abc> <>                |   0| 1:BRANCH(3)
   3 <abc> <>                |   1|  2:REG_ANY(5)
                             |   1|  failed...
   3 <abc> <>                |   0| 3:BRANCH(5)
   3 <abc> <>                |   1|  4:SEOL(5)
   3 <abc> <>                |   1|  5:END(0)
END: Match possible, but length=0 is smaller than requested=1, failing!
                             |   0| BRANCH failed...
Match failed
Freeing REx: ".|$"

##</code><code>##

my $str = "abc";
print $str =~ m/(.)|$/g ? "matched! ".($1//'$') : 'no match', "\n"
	for 1..5;

__END__

matched! a
matched! b
matched! c
matched! $
no match