First off: always use strictures (use strict; use warnings;).

Second: you don't need to initialize arrays and hashes. Your declarations should look like:

my %seen;
my @unique;
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Avoid extra nesting. Refactor the loop as:

foreach my $item (@proc_name1) {
    next if $seen{$item};

    $seen{$item} = 1;
    push (@uniq, $item);
}
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However, if you don't need to know the order that the items were seen then you don't need the array and can just:

my %seen;

$seen{$_}++ for @proc_name1;
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or using a hash slice you could:

my %seen;

@seen{@proc_name1} = ();
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In either case keys %seen gives the list of unique proc names.