diff --git a/README.md b/README.md
index a6b44aa..886e7bb 100644
--- a/README.md
+++ b/README.md
@@ -104,7 +104,7 @@ Download the first 3 sources and then use the `util_add_taxa.py` script to extra
 ## Tests
 There are tests which you can run like so:
 ```bash
-expor  MOCK_DATA=1; python -m unittest discover
+export  MOCK_DATA=1; python -m unittest discover
 ```
 
 Please `export MOCK_DATA=0` before you run any scripts on real data.