in reply to I'd like to have an indication when the interpreter moves to the next file (using Filter-Include)?

There is no way to do this through the current interface, but you can bodge it e.g
BEGIN { require Filter::Include; my $old_source = *Filter::Include::source{CODE}; *Filter::Include::source = sub { print "Including $_[0]\n"; goto &$old_source; }; Filter::Include->import; }
I could add this feature to the module if you'd like (probably as an import() parameter), it could do with some tidying up anyhow.