A little more optimized than the first few - and more true to the request - plus keeping them in order - plus features.

sub util_remove_duplicates {
  my $ref = ref($_[0]) ? shift() : [@_];
  my %hash;
  for (my $i = 0; $i <= $#$ref; $i ++) {
    if (! $hash{$ref->[$i]}) {
      $hash{$ref->[$i]} = 1;
      next;
    }
    splice @$ref, $i, 1;
    $i --;
  }
  return wantarray ? @$ref : $ref;
}


my @a = qw(a a b c d a d c a e);

util_remove_duplicates(\@a); # works
my @B = util_remove_duplicates(\@a); # works and returns array to @B
my $B = util_remove_duplicates(\@a); # works and returns array ref to 
+$B
my $B = util_remove_duplicates(@a); # works without modifying @a
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my @a=qw(random brilliant braindead); print $a[rand(@a)];