$var A scalar variable (string, number, or pointer)
@list A complete list.
$#list Highest index of a list.
$list[$index] An element of a list at position index.
@list[$i..$j] A part of a list.
push(@list,$var) Add an element to a list.
pop(@list) Delete last element from a list.
%hash A complete hash.
$hash{$key} One element identified by key.
keys %hash All keys of a hashes a list.
values %hash All values of a hash as a list.