diff --git a/README.md b/README.md
index 9c18e2a..57af3dd 100644
--- a/README.md
+++ b/README.md
@@ -3,3 +3,13 @@
 monitors a list of SYMPA servers and
 reports the failed ones
 
+## prerequired
+
+* GNU Parallel `sudo apt install parallel`
+
+## execute
+
+```bash
+bash all.sh
+```
+