diff --git a/README.md b/README.md
index ba58a6c..5522628 100644
--- a/README.md
+++ b/README.md
@@ -52,7 +52,7 @@ export CTRLG_TMUX=true
 ### Fish
 
 ```
-set -U CTRLG_TMUX true
+set CTRLG_TMUX true
 ```
 
 ## Configuration