my $x = {
    'Moby Dick' => "The entire text of Moby Dick...",
    'The Lord of the Rings' => "The entire text of Lord of the Rings...",
    'Great Expectations' => "The entire text of Great Expectations...",
    'War and Peace' => "The entire text of War and Peace...",
};

##</code><code>##

my $books = lock_retrieve('books.data');

##</code><code>##

my $search_string = 'ect';
foreach $title (keys %$books) {
    print $books->{$title} if $title =~ /$search_string/i;
}