Perl file commenter

#
#author: Todd Davies
#use: Appends a comment to java, pl and txt files in a directory with my name!
#warning: It's probably best not to use it on anything other than text based files!
#

use Switch;

@files = <*>;
foreach $filename (@files) {
    my $new_fn = $filename . '.new';
    open my $in, '<', $filename or die "Cannot open $filename for reading - $!";
    open my $out, '>', $new_fn or die "Cannot open $new_fn for writing - $!";

    my $ext = ($filename =~ m/([^.]+)$/)[0];
    switch ($ext) {
        case "txt"  { print {$out} "--------------------------\nauthor: Todd Davies\n--------------------------\n";   }
        case "java" { print {$out} "/*\n *author: Todd Davies\n */\n";  }
        case "pl"   { print {$out} "#\n#author: Todd Davies\n#\n";  }
        else        {  }
    }

    while (my $line = <$in>)
    {
        print {$out} $line;
    }

    close($out);
    close($in);
    rename($new_fn, $filename);
    print "Processed: ".$filename."\n";
}
<>;