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The freed up memory is not returned to the system, rather the freed up memory is used for possible declarations of new lexically scoped variables that could be declared later in the program. This means that your program will never get smaller because of lexical variables going of of scope. Once the memory is allocated for perl, it remains under perl's jurisdiction. But perl can use garbage collected space for other lexical variables. If a lexical variable is a referent of another variable, then the lexical will not be garbage collected when it goes out of scope.

39 When you refer to an entire hash, use the "%" sigil. my %info = qw ( name John age 42 ); When you look up a key in the hash, the "%" character changes to a "$" and the key is placed in curly braces. my %info = qw ( name John age 42 ); my $data = $info{name}; warn $data; > John ... The keys of a hash are not pre-declared. If the key does not exist during an ASSIGNMENT, the key is created and given the assigned value. my %inventory; $inventory{apples}=42; $inventory{pears}=17; $inventory{bananas}=5; print Dumper \%inventory; >$VAR1 = { > 'bananas' => 5, > 'apples' => 42, > 'pears' => 17 > }; If the key does not exist during a FETCH, the key is NOT created, and undef is returned.

You can create variables in ANY namespace you want, without ever having to declare the namespace explicitly. You can even declare variables in someone else's package namespace. There is no restrictions in perl that prevent you from doing this. To encourage programmers to play nice with each other's namespaces, the "our" function was created. Declaring a variable with "our" will create the variable in the current namespace. If the namespace is other than "main", then you will need to declare the package namespace explicitly.