$ perl -le'
use warnings;
use strict;

package Foo; # this creates a package called Foo
my $Foo::bar = "Hello World";
'
"my" variable $Foo::bar can't be in a package at -e line 6, near "my $Foo::bar "
Execution of -e aborted due to compilation errors.


##</code><code>##

$ perl -le'
use warnings;
use strict;

package Foo; # this creates a package called Foo
$Foo::bar = "Hello World";

package main; # goes back to default package of class
print $Foo::bar; # this prints $bar form package Foo
'
Hello World