diff --git a/book/README.md b/book/README.md
index 8af5a7ec..79a061fb 100644
--- a/book/README.md
+++ b/book/README.md
@@ -39,7 +39,7 @@ gitbook:examples $ c++ -std=c++11 intro.cpp
 Much more complicated options are handled elegantly:
 
 ```cpp
-std::string req_real_file;
+std::string file;
 app.add_option("-f,--file", file, "Require an existing file")
   ->required()
   ->check(CLI::ExistingFile);