use 5.010;

##</code><code>##

    if ($input =~ /^(y|yes)$/) {
        say "Backup is beginning...";
        last;
    }
    elsif ($input =~ /^(n|no)$/) {
        die "Program is shutting down.\n";
    }
    else {
        say "This is not a valid answer.";
        say "Please enter 'yes' or 'no'";
    }

##</code><code>##

    if ($input eq 'y' || $input eq 'yes') {
        say "Backup is beginning...";
        last;
    }