open( FD, "$ARGV[0]") or die "die.\n";
open( FD2, ">test");
#if (!open( FD, "$ARGV[0]")){
#    print "File ";
#    print $ARGV[0];
#    print " didn't found.\n";
#    exit(-1);
#}

$flag = 0;
$glbl = "module glbl ();\n";
$end  = "endmodule\n";
$comment = "//";
while($line = <FD>){
    if ( $line eq $glbl) {
	$flag = 1;	
    }
    
    if ( $flag == 1){
	print FD2 $comment.$line;
	if ( $line eq $end){
	    $flag = 0;
	}
    } else {
	print FD2 $line;
    }

}

close( FD);
close( FD2);

system "mv test $ARGV[0]";