Update README.md

README.md

@@ -177,6 +177,13 @@ if network required between host and docker container on a macvlan docker networ
 
 write to docker log buffer
 
- ``` 
+``` bash
 echo "Hello World!" >> /proc/1/fd/1
-``` 
+``` 
+
+clear all docker logs
+
+``` bash
+truncate -s 0 /var/lib/docker/containers/*/*-json.log;
+``` 
+