Update README.md

Author: devlights

README.md

@@ -51,3 +51,38 @@ $ cd cmd/readwrite2/client
 $ go run .
 ```
 
+### Using encoding/gob package
+
+Open two terminals. the one is following:
+
+```sh
+$ cd cmd/usinggob/server
+$ go run .
+```
+
+and another terminal is following:
+
+```sh
+$ cd cmd/usinggob/client
+$ go run .
+```
+
+## Monitor a local unix domain socket
+
+use socat. install it if not exists.
+
+```sh
+$ sudo apt install -y socat
+```
+
+and launch server program then input following commands.
+
+```sh
+$ mv /tmp/echo.sock /tmp/echo.sock.original
+$ socat -t100 -x -v UNIX-LISTEN:/tmp/echo.sock,mode=777,reuseaddr,fork UNIX-CONNECT:/tmp/echo.sock.original
+```
+
+### REFERENCES
+
+[Can I monitor a local unix domain socket like tcpdump?](https://superuser.com/questions/484671/can-i-monitor-a-local-unix-domain-socket-like-tcpdump)
+