This appears to work correctly: 

my @ranges = [ 0 ];
while ( <INTERVAL> ) {
        my ( undef, $start, $end ) = split;
        push @{ $ranges[ -1 ] }, $start - 1;
        push @ranges, [ $end ];
        }
push @{ $ranges[ -1 ] }, length $mask;

for my $range ( @ranges ) {
        my ( $start, $end ) = @$range;
        next if $start == $end;
        substr( $mask, $start, $end - $start ) =~ tr//N/c;
        }

print "$mask\n";

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In reply to Re: Trouble with Transliterate Function by jwkrahn
in thread Trouble with Transliterate Function by ccelt09

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