perl监控目录变化

File::ChangeNotify

试过windows可以，注意filter参数

cpan例子：

    use File::ChangeNotify;

    my $watcher =
        File::ChangeNotify->instantiate_watcher
            ( directories => [ '/my/path', '/my/other' ],
              filter      => qr/\.(?:pm|conf|yml)$/,
            );

    if ( my @events = $watcher->new_events() ) { ... }

    # blocking
    while ( my @events = $watcher->wait_for_events() ) { ... }