#!/usr/bin/perl -w
use strict;

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

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

__END__

Hello World
[download]

Just for completeness, our is like my not restricted to the scope of the package.

So this example can be simplified as long as the packages are not enclosed in a block or in different files.

#!/usr/bin/perl -w
use strict;
 
{
  package Foo; 
  our $bar = "Hello World";
 
  package Zoo;
  print $bar; # no "Foo::" necessary 
}
 
print $Foo::bar; #  now again in package main
 
__END__
Hello WorldHello World
[download]

Cheers Rolf

Thank you! This is just what i needed :)

Any variable you see that has a double colon (Foo::bar) or apostrophe (Foo'bar) in it is a package variable.    Any variable created with my is not a package variable.

$ 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.
[download]

$ 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
[download]

toolic covered it but you may also want to read: Lexical scoping like a fox

Ahh,, this explanation makes alot of sense! thank you!

A variable declared with my is scoped until the end of it's block or if it is outside of any block, to the end of the file. Thus, this works:

package Foo;
my $bar = 'Hello World';

package main;
print "$bar\n";

A variable declared with our is global and can be accessed by a fully-qualified name. Example: $Foo::bar.

See perldoc perlmod for details on fully-qualified names.