I once wrote one of these before for @NegativeMjark but I think I lost it. So here's another.
All you need to know is:
$foois a scalar (i.e. a single dimensional variable)@foois an array.$foo[n]is the element of an array.%foois a hash.$foo{'moo'}aka$foo{moo}is the value in the hash for key'foo'.\is the reference operator. it returns a scalar which points to the address of the variable (like&in C).(1, 2, 3)is a list. (an array is a variable which contains a list).[1, 2, 3](rarely:\(1,2,3)) is a reference to a list - aka arrayref$foo->[n]gives an element of an arrayref