diff --git a/reading/command_line.livemd b/reading/command_line.livemd
index 4c84467b..11af6afe 100644
--- a/reading/command_line.livemd
+++ b/reading/command_line.livemd
@@ -99,7 +99,7 @@ IO.puts("Hello, world!")
 Then execute the file from the command line. Any Elixir code inside of the file will execute.
 
 ```
-$ elixir script.ex
+$ elixir script.exs
 Hello, world!
 ```