Add more description to Port Forwarding.

_2020/command-line.md

@@ -376,7 +376,7 @@ comes in two flavors: Local Port Forwarding and Remote Port Forwarding (see the
 **Remote Port Forwarding**
 ![Remote Port Forwarding](https://i.stack.imgur.com/4iK3b.png  "Remote Port Forwarding")
 
-The most common scenario is local port forwarding, where a service in the remote machine listens in a port and you want to link a port in your local machine to forward to the remote port. For example, if we execute  `jupyter notebook` in the remote server that listens to the port `8888`. Thus, to forward that to the local port `9999`, we would do `ssh -L 9999:localhost:8888 foobar@remote_server` and then navigate to `locahost:9999` in our local machine.
+The most common scenario is local port forwarding, where a service in the remote machine listens in a port and you want to link a port in your local machine to forward to the remote port. For example, if we execute  `jupyter notebook` in the remote server that listens to the port `8888`. Thus, to forward that to the local port `9999`, we would do `ssh -L 9999:localhost:8888 foobar@remote_server` and then navigate to `locahost:9999` in our local machine. Note: the meaning of the syntax is when you connect to `localhost:9999` in your local machine, it will send the data via SSH(default on port 22)to the remote server(`foobar@remote_server` at the top)and only after that the remote server will send the data to destination server you had assign(`localhost:8888` at the top).
 
 
 ## SSH Configuration