use strict;
use warnings;

use 5.010;

my @searches = qw{
   .LLL
   LLLL
   .RRR
   RRRR
   };
                
chomp( my @lines = <DATA> );

foreach my $search ( @searches )
{
    my $rxSearch = qr{(?=\Q$search\E)};
    my $length   = length $search;
    foreach my $line ( @lines )
    {
        my ( $string, $mask ) = split m{\s+}, $line, 2;
        say qq{Looking for '$search' in '$mask'};

        while ( $mask =~ m{$rxSearch}g )
        {
            my $pos = pos $mask;
            my $ind = q{ } x length $mask;
            substr $ind, $pos, $length, q{^} x $length;
            say qq{     Found at offset $pos};
            say qq{     $string\n     $mask};
            say qq{     $ind - @{ [ substr $string, $pos, $length ] }};
        }
    }
}


__DATA__
THAETURQU			.LLL..RRR
JURYATAUTIOPW			.LLL...LL.RRR
TURIWOWQNQQUTYRIOPWMNHF		L..L..LLLL.LL.R..L.LLLL