diff --git a/compiler/cpp/README.md b/compiler/cpp/README.md
index 77cb234..2fff0d8 100644
--- a/compiler/cpp/README.md
+++ b/compiler/cpp/README.md
@@ -79,7 +79,7 @@
 From a command prompt:
 ```
 cd thrift/compiler/cpp
-flex -osrc\thrift\thriftl.cc src\thrift\thriftl.ll
+flex -o src\thrift\thriftl.cc src\thrift\thriftl.ll
 ```
 In the generated thriftl.cc, comment out #include <unistd.h>