bla.pl
------
BEGIN { $|=1 }
use bla ();
$planet = "World\n";
print($planet);


bla.pm
------
$greet = "Hello\n";
print($greet);


>perl -Mstrict bla.pl
Hello
Global symbol "$planet" requires explicit package name at bla.pl line 3.
Global symbol "$planet" requires explicit package name at bla.pl line 4.
Execution of bla.pl aborted due to compilation errors.