diff --git a/tools/unix2dos.pl b/tools/unix2dos.pl
index f387376da6..6ebb12d67b 100755
--- a/tools/unix2dos.pl
+++ b/tools/unix2dos.pl
@@ -27,7 +27,9 @@
 use strict;
 
 while (<STDIN>) {
-	$_ =~ s/\n/\r\n/;
+	if($_ !~ /\r\n/) {
+		$_ =~ s/\n/\r\n/;
+	}
 	print $_;
 }
 1;