### fee_file.pl use strict; use warnings; $main::fee = 0xfee; __END__ Produces the warning message: Name "main::fee" used only once: possible typo at ... #### ### foo_file.pl use strict; use warnings; require "fee_file.pl"; my $foo; print $main::fee; print $foo = 12; __END__ Produces the warning message: Name "main::fee" used only once: possible typo at ... #### ### perl $foo = 1; ### python foo = 1 #### ### perl print "Hello $foo." ### 19 chars ### python print "Hello "+foo+".", ### 23 chars