Have you used the "Search" box or Super Search to find an answer? Searching for "Removing duplicates", I find Removing Duplicates from an Array and Removing Duplicates in an array?. Searching with Google, the first hit already is an answer. perldoc -q duplicate has the FAQ on that question.

In short, you want to keep track of all items you've already seen, for which a hash is a convenient datastructure:

my %seen;
for my $item (@array) {
  $seen{$item}++ # remember this item
};

my @unique = keys %seen;
# The order gets lost though
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