If you need to maintain the original order and delete subsequent duplicates, you could try this.

{
    my %seen;
    my ($in_file, $out_file) = qw| in.txt out.txt|;
    open my $in_fh, $in_file or die "$in_file: $!";
    open my $out_fh, '>', $out_file or die "$in_file: $!";
    while ( <$in_fh> ) {
        print $out_fh $_ unless $seen{$_}++;
    }
}
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HTH,
Charles K. Clarkson


Why isn't phonetic spelled the way it sounds?