diff --git a/README.md b/README.md
index 8c60faa..00c6b8c 100644
--- a/README.md
+++ b/README.md
@@ -11,3 +11,15 @@ Format and reformat ascii proof trees like this one:
 §  ---------------------------------------------------------------------- RewriteAt
 §                         [x:=*;][?x>0;x:=x+1;]x>1
 ```
+
+To reformat all proof trees in your project, run:
+
+```shell
+java -jar asciiprooftree.jar path/to/your/src
+```
+
+If you want to use a different marker string than `§`, you can use the `--marker` option:
+
+```shell
+java -jar asciiprooftree.jar path/to/your/src --marker 't>'
+```