#!/usr/bin/perl -w
use strict;
use Data::Dumper;

my @array = (
    { a => 1, b => 2, c => 3},
    { b => 1, d => 2, c => 3},
    { a => 1, b => 2, c => 3},
    { a => 2, b => 2, c => 3},
    { a => 2, b => 1, c => 3},
);

my %count;
my @unique;

    # eats away at @array, use for() if you want to keep it
while (my $entry = shift @array) { 

    # need to sort by something because an equivalent hash migh
    # return the key/value pairs in a different order
    my @sorted = map { $_, $entry->{$_} } sort keys %$entry;

    # create a unique string and see if we've seen it before
    next if $count{ join"#",@sorted }++;

    push @unique,$entry;
}
print Dumper(\@unique);