diff --git a/README.md b/README.md
index 7cdafa68893bf7113be405102b0214f73e465462..53536c75cb6a6f64cb4cd1eab410d1bdf910ef4a 100644
--- a/README.md
+++ b/README.md
@@ -274,7 +274,7 @@ The confusion matrices are informative, but they do not tell us things such as w
 To get this more detailed error analysis in the form of graph-level *confusion histograms*, we can issue:
 
 ```
-confHist tests/io_tests/small-out tests/io_tests/small-GT --graph-size 1
+confHist tests/io_tests/small-out tests/io_tests/small-GT --graphSize 1
 ```
 
 This produces the following output directory, with an HTML file and subdirectories as shown: